NFC: Refactor ProcessWinMiniDump to use a more traditional pimpl idiom.
This is a mechanical refactor. There should be no functional changes in this commit.
Instead of encapsulating just the Windows-specific data, ProcessWinMiniDump now uses a private implementation class. This reduces indirections (in the source). It makes it easier to add private helper methods without touching the header and allows them to have platform-specific types as parameters. The only trick was that the pimpl class needed a back pointer in order to call a couple methods.
llvm-svn: 262256