Fixed a problem where evaluating a breakpoint
condition in two different processes (with the
same target) could cause crashes.  Now the breakpoint
condition is always evaluated (and possibly parsed)
by one thread at a time.

<rdar://problem/14083737>


git-svn-id: https://llvm.org/svn/llvm-project/lldb/trunk@183440 91177308-0d34-0410-b5e6-96231b3b80d8