[SanitizerCoverage] Give clang-cc1 the power to precisly specify needed sanitizier coverage mode.

Summary:
The next step is to add user-friendly control over these options
to driver via -fsanitize-coverage= option.

Test Plan: regression test suite

Reviewers: kcc

Subscribers: cfe-commits

Differential Revision: http://reviews.llvm.org/D9545

llvm-svn: 236756