Provide OS thread ID and name in -thread-info response

[jld01]

No description provided.

[jld01]

Previously, the LLDB-MI -thread-info command returned the LLDB-allocated thread index ID in the target-id field (duplicating information in the id field).

906,787 115-thread-info
906,803 115^done,threads=[{id="3",target-id="Thread 3" ...}, ...

If the thread had a valid name, this was provided in the target-id field instead of the index ID:

906,787 115-thread-info
906,803 115^done,threads=[{id="3",target-id="MyThreadName", ...}, ...

This change brings behaviour in line with GDB/MI which returns the OS-allocated thread ID in target-id and the thread name in name (if present):

906,787 115-thread-info
906,803 115^done,threads=[{id="3",target-id="Thread 10367",name="MyThreadName", ...}, ...

[jld01]

@sunshaoce, I am not sure why the original code tests the thread name for validity using CMIUtilString::IsAllValidAlphaAndNumeric(pThreadName). This seems unnecessarily restrictive. I think spaces and punctuation characters should be acceptable in a thread name, perhaps using a method backed by isprint() rather than isalnum(). What is your opinion? We would need avoid or escape the double quote char (") for MI.

[sunshaoce]

The change itself looks fine. However, since lldb-mi has very limited test coverage, being conservative about relaxing thread name validation is probably safer for now.

[jld01]

OK, could you review this PR in it's current state, then, please?

[sunshaoce]

LGTM. Thanks for contributing!