Lldb support code for mono (#4225)
* Initial version of lldb support code.
* [lldb] Keep all the debug entries in a linked list so lldb can read it after attaching to the process.
* [lldb] Add an --enable-minimal=lldb option to disable the code. Add locking.
* [lldb] Add support for dynamic methods by adding a new protocol entry for unloading code regions.
* [lldb] Add beginnings of a test suite using the lldb python bindings.
* [lldb] Emit line number info for methods, not used yet.
* [lldb] Add dummy fields to structures to make sure 64 bit fields are 64 bit aligned.
* [lldb] Finish emission of line number info.
* [lldb] Use mono_method_full_name () for computing method names.
* [lldb] Emit info for specific trampolines as well.
* [lldb] Add tests for line number info.
* [lldb] Fix unwind info encoding on x86.
* [lldb] Skip seq points with no native offset.
* [lldb] Add tests for breakpoints.