Replace uses of MIUtilParse::CRegexParser with llvm::Regex

Summary:
Replace uses of the local MIUtilParse::CRegexParser class with the LLVM support class llvm::Regex. This reduces duplication of code, and makes it possible to remove the MIUtilParse::CRegexParser class that requires LLVM internal implementation headers.

Bug: https://llvm.org/bugs/show_bug.cgi?id=29138

Reviewers: dawn, abidh, ki.stfu

Subscribers: labath, ki.stfu, lldb-commits

Differential Revision: https://reviews.llvm.org/D23882
Author:	Michał Górny <mgorny@gentoo.org>

llvm-svn: 280662