Remove support for building sanitizers from Makefile/autoconf build on Linux.

This is a re-application of r229554 restricted to Linux build only.
Apple still uses Makefile/autoconf to build Clang and sanitizers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@229755 91177308-0d34-0410-b5e6-96231b3b80d8