Fix 'dg-warning' in 'c-c++-common/Wfree-nonheap-object-3.c' for C++

Fix 'dg-warning' in 'c-c++-common/Wfree-nonheap-object-3.c' for C++

    [...]/c-c++-common/Wfree-nonheap-object-3.c:57:24: warning: 'malloc (dealloc_float)' attribute ignored with deallocation functions declared 'inline' [-Wattributes]
    [...]/c-c++-common/Wfree-nonheap-object-3.c:51:1: note: deallocation function declared here
    [...]/c-c++-common/Wfree-nonheap-object-3.c: In function 'void test_nowarn_int(int)':
    [...]/c-c++-common/Wfree-nonheap-object-3.c:25:20: warning: 'void __builtin_free(void*)' called on pointer 'p' with nonzero offset 4 [-Wfree-nonheap-object]
    [...]/c-c++-common/Wfree-nonheap-object-3.c:24:24: note: returned from 'int* alloc_int(int)'
    [...]/c-c++-common/Wfree-nonheap-object-3.c: In function 'void test_nowarn_long(int)':
    [...]/c-c++-common/Wfree-nonheap-object-3.c:45:18: warning: 'void dealloc_long(long int*)' called on pointer '<unknown>' with nonzero offset 8 [-Wfree-nonheap-object]
    [...]/c-c++-common/Wfree-nonheap-object-3.c:44:26: note: returned from 'long int* alloc_long(int)'
    In function 'void dealloc_float(float*)',
        inlined from 'void test_nowarn_float(int)' at [...]/c-c++-common/Wfree-nonheap-object-3.c:68:19:
    [...]/c-c++-common/Wfree-nonheap-object-3.c:53:18: warning: 'void __builtin_free(void*)' called on pointer '<unknown>' with nonzero offset 8 [-Wfree-nonheap-object]
    [...]/c-c++-common/Wfree-nonheap-object-3.c: In function 'void test_nowarn_float(int)':
    [...]/c-c++-common/Wfree-nonheap-object-3.c:67:28: note: returned from 'float* alloc_float(int)'
    PASS: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for warnings, line 25)
    FAIL: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for warnings, line 45)
    PASS: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for warnings, line 51)
    PASS: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for warnings, line 53)
    PASS: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98  (test for warnings, line 57)
    FAIL: c-c++-common/Wfree-nonheap-object-3.c  -std=gnu++98 (test for excess errors)
    Excess errors:
    [...]/c-c++-common/Wfree-nonheap-object-3.c:45:18: warning: 'void dealloc_long(long int*)' called on pointer '<unknown>' with nonzero offset 8 [-Wfree-nonheap-object]

..., that is: decorated 'void dealloc_long(long int*)' instead of plain
'dealloc_long' -- similar to how all the other 'dg-warning's allow for the
decorated function signature in addition to the plain one.

This issue was latent since the test case was added in
commit fe7f75cf16783589eedbab597e6d0b8d35d7e470
"Correct/improve maybe_emit_free_warning (PR middle-end/98166, PR c++/57111, PR middle-end/98160)",
and was finally exposed by my recent
commit 9c03391ba447ff86038d6a34c90ae737c3915b5f
"Tighten 'dg-warning' alternatives in 'c-c++-common/Wfree-nonheap-object{,-2,-3}.c'".

	gcc/testsuite/
	* c-c++-common/Wfree-nonheap-object-3.c: Fix 'dg-warning' for C++.