[sanitizer] Require that options end with '='.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@209814 91177308-0d34-0410-b5e6-96231b3b80d8
[sanitizer] Add coverage_dir flag.


git-svn-id: https://llvm.org/svn/llvm-project/compiler-rt/trunk@209815 91177308-0d34-0410-b5e6-96231b3b80d8