tsan: improve "destroy of a locked mutex" reports

1. Allow to suppress by current stack.
We generally allow to suppress by all main stacks.
Current is probably the stack one wants to use to
suppress such reports.

2. Fix last lock stack restoration.
We trimmed shadow value by storing it in u32.
This magically worked for the test that provoked
the report on the main thread. But this breaks
for locks in any other threads.

llvm-svn: 331023