[Driver] Support for disabling sanitizer runtime linking

This change introduces a pair of -fsanitize-link-runtime and
-fno-sanitize-link-runtime flags which can be used to control linking of
sanitizer runtimes. This is useful in certain environments like kernels
where existing runtime libraries cannot be used.

Differential Revision: https://reviews.llvm.org/D65029

llvm-svn: 367794