[ASan] Move the SIGSEGV/SIGBUS handling to sanitizer_common

This change is a part of refactoring intended to have common signal handling behavior in all tools.
This particular CL moves InstallSignalHandlers() into sanitizer_common (making it InstallDeadlySignalHandlers()), but doesn't enable default signal handlers for any tool other than ASan.



git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@200542 91177308-0d34-0410-b5e6-96231b3b80d8