[sanitizer] Expose __sanitizer_print_stack_trace().

Expose a new interface function for debugging code built with sanitizer tools.
Add an ASan implementation.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@196302 91177308-0d34-0410-b5e6-96231b3b80d8
[asan] Fix build error.

git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@196303 91177308-0d34-0410-b5e6-96231b3b80d8