[Sanitizer] Replace Symbolizer::IsAvailable and Symbolizer::IsExternalAvailable with Symbolizer::CanReturnFileLineInfo.
Remove now redundant checks in symbolizer initialization in TSan and MSan.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@198000 91177308-0d34-0410-b5e6-96231b3b80d8