Allow specifying sanitizers in blacklists

Summary:
This is the follow-up patch to D37924.

This change refactors clang to use the the newly added section headers
in SpecialCaseList to specify which sanitizers blacklists entries
should apply to, like so:

  [cfi-vcall]
  fun:*bad_vcall*
  [cfi-derived-cast|cfi-unrelated-cast]
  fun:*bad_cast*

The SanitizerSpecialCaseList class has been added to allow querying by
SanitizerMask, and SanitizerBlacklist and its downstream users have been
updated to provide that information. Old blacklists not using sections
will continue to function identically since the blacklist entries will
be placed into a '[*]' section by default matching against all
sanitizers.

Reviewers: pcc, kcc, eugenis, vsk

Reviewed By: eugenis

Subscribers: dberris, cfe-commits, mgorny

Differential Revision: https://reviews.llvm.org/D37925

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@314171 91177308-0d34-0410-b5e6-96231b3b80d8