Extend SpecialCaseList to allow users to blame matches on entries in the file.

Summary:
Extends SCL functionality to allow users to find the line number in the file the SCL is built from through SpecialCaseList::inSectionBlame(...).

Also removes the need to compile the SCL before use. As the matcher now contains a list of regexes to test against instead of a single regex, the regexes can be individually built on each insertion rather than one large compilation at the end of construction.

This change also fixes a bug where blank lines would cause the parser to become out-of-sync with the line number. An error on line `k` was being reported as being on line `k - num_blank_lines_before_k`.

Note: This change has a cyclical dependency on D39486. Both these changes must be submitted at the same time to avoid a build breakage.

Reviewers: vlad.tsyrklevich

Reviewed By: vlad.tsyrklevich

Subscribers: kcc, pcc, llvm-commits

Differential Revision: https://reviews.llvm.org/D39485

llvm-svn: 317617