[runtime] fix warnings on linux (gcc 8.3.0) (#18479)

[runtime] fix warnings on linux (gcc 8.3.0) (#18479)

* [aot] fix warnings on linux (gcc 8.3.0)

Fixes these warnings:
```
aot-compiler.c: In function ‘emit_trampolines’:
aot-compiler.c:7675:28: warning: ‘_e’ directive writing 2 bytes into a region of size between 1 and 256 [-Wformat-overflow=]
    sprintf (end_symbol, "%s_e", symbol);
                            ^~
aot-compiler.c:7675:4: note: ‘sprintf’ output between 3 and 258 bytes into a destination of size 256
    sprintf (end_symbol, "%s_e", symbol);
    ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
At top level:
aot-compiler.c:753:1: warning: ‘link_shared_library’ defined but not used [-Wunused-function]
 link_shared_library (MonoAotCompile *acfg)
 ^~~~~~~~~~~~~~~~~~~
aot-compiler.c:558:1: warning: ‘mangle_symbol_alloc’ defined but not used [-Wunused-function]
 mangle_symbol_alloc (const char * symbol)
 ^~~~~~~~~~~~~~~~~~~
aot-compiler.c:535:1: warning: ‘mangle_symbol’ defined but not used [-Wunused-function]
 mangle_symbol (const char * symbol, char * mangled_symbol, gsize length)
 ^~~~~~~~~~~~~~~~~~~
```

* [amd64] fix warnings on linux (gcc 8.3.0)

Fixes this warning:
```
tramp-amd64.c: In function ‘mono_arch_create_generic_trampoline’:
tramp-amd64.c:242:65: warning: variable ‘ex_offset’ set but not used [-Wunused-but-set-variable]
  int i, lmf_offset, offset, res_offset, arg_offset, rax_offset, ex_offset, tramp_offset, ctx_offset, saved_regs_offset;
                                                                 ^~~~~~~~~
```

* [lldb] fix warnings on linux (gcc 8.3.0)

Fixes these warnings:
```
lldb.c:243:1: warning: ‘buffer_add_buffer’ defined but not used [-Wunused-function]
 buffer_add_buffer (Buffer *buf, Buffer *data)
 ^~~~~~~~~~~~~~~~~
lldb.c:215:1: warning: ‘buffer_add_id’ defined but not used [-Wunused-function]
 buffer_add_id (Buffer *buf, int id)
 ^~~~~~~~~~~~~
lldb.c:208:1: warning: ‘buffer_add_long’ defined but not used [-Wunused-function]
 buffer_add_long (Buffer *buf, guint64 l)
 ^~~~~~~~~~~~~~~
lldb.c:188:1: warning: ‘buffer_add_short’ defined but not used [-Wunused-function]
 buffer_add_short (Buffer *buf, guint32 val)
 ^~~~~~~~~~~~~~~~

```

* [interp] fix warnings on linux (gcc 8.3.0)

Fixes these warnings:
```
interp/interp.c:3425:1: warning: ‘g_error_xsx’ defined but not used [-Wunused-function]
 g_error_xsx (const char *format, int x1, const char *s, int x2)
 ^~~~~~~~~~~
  CC       interp/libmono_ee_interp_la-mintops.lo
  CC       interp/libmono_ee_interp_la-transform.lo
  CCLD     libmono-ee-interp.la
ar: `u' modifier ignored since `D' is the default (see `U')
  CC       libmono_dbg_la-debugger-agent.lo
  CC       libmono_dbg_la-debugger-state-machine.lo
  CC       libmono_dbg_la-debugger-engine.lo
  CCLD     libmono-dbg.la
ar: `u' modifier ignored since `D' is the default (see `U')
  CCLD     mono-sgen
  AR       libmain.a
ar: `u' modifier ignored since `D' is the default (see `U')
  CC       interp/libmaintest_a-whitebox.o
In file included from interp/whitebox.c:3:
interp/transform.h:163:12: warning: ‘stack_type’ defined but not used [-Wunused-variable]
 static int stack_type [] = {
            ^~~~~~~~~~
interp/transform.h:155:20: warning: ‘stack_type_string’ defined but not used [-Wunused-variable]
 static const char *stack_type_string [] = { "I4", "I8", "R4", "R8", "O ", "VT", "MP", "F " };
                    ^~~~~~~~~~~~~~~~~

```

* [thread state] fix warnings on linux (gcc 8.3.0)

Fixes these warnings:
```
  CC       libmonoutils_la-mono-threads-state-machine.lo
mono-threads-state-machine.c:33:1: warning: ‘get_thread_no_safepoints’ defined but not used [-Wunused-function]
 get_thread_no_safepoints (int thread_state)
 ^~~~~~~~~~~~~~~~~~~~~~~~
mono-threads-state-machine.c:26:1: warning: ‘get_thread_suspend_count’ defined but not used [-Wunused-function]
 get_thread_suspend_count (int thread_state)
 ^~~~~~~~~~~~~~~~~~~~~~~~
```

* [domain] fix warnings on linux (gcc 8.3.0)

Fixes these warnings:
```
appdomain.c:2415:1: warning: ‘get_app_context_base_directory’ defined but not used [-Wunused-function]
 get_app_context_base_directory (MonoError *error)
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  CC       libmonoruntimesgen_la-assembly-load-context.lo
  CC       libmonoruntimesgen_la-domain.lo
domain.c:135:1: warning: ‘mono_domain_alcs_lock’ declared ‘static’ but never defined [-Wunused-function]
 mono_domain_alcs_lock (MonoDomain *domain);
 ^~~~~~~~~~~~~~~~~~~~~
domain.c:138:1: warning: ‘mono_domain_alcs_unlock’ declared ‘static’ but never defined [-Wunused-function]
 mono_domain_alcs_unlock (MonoDomain *domain);
 ^~~~~~~~~~~~~~~~~~~~~~~
domain.c:2129:1: warning: ‘mono_alc_free’ defined but not used [-Wunused-function]
 mono_alc_free (MonoAssemblyLoadContext *alc)
 ^~~~~~~~~~~~~
domain.c:2108:1: warning: ‘mono_domain_create_default_alc’ defined but not used [-Wunused-function]
 mono_domain_create_default_alc (MonoDomain *domain)
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
domain.c:2084:1: warning: ‘create_alc’ defined but not used [-Wunused-function]
 create_alc (MonoDomain *domain, gboolean is_default)
 ^~~~~~~~~~

```

* [native library] fix warnings on linux (gcc 8.3.0)

Fixes this warning:
```
  CC       libmonoruntimesgen_la-native-library.lo
native-library.c:295:1: warning: ‘mono_loader_register_module_locking’ defined but not used [-Wunused-function]
 mono_loader_register_module_locking (const char *name, MonoDl *module)
 ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
```

* [sample] fix warnings on linux (gcc 8.3.0)

Fixes this warning:
```
  CC       libtestlib_la-test-mono-embed.lo
In file included from test-mono-embed.c:7:
../../samples/embed/teste.c:20:1: warning: function declaration isn’t a prototype [-Wstrict-prototypes]
 gimme () {
 ^~~~~

```

* fix for checked builds