Basic/Diagnostics: Add a DiagnosticIDs::getDiagnosticsInGroup method, and use
that in DiagnosticEngine instead of the convoluted calling into DiagnosticIDs
which then calls back into the DiagnosticsEngine.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@140766 91177308-0d34-0410-b5e6-96231b3b80d8
4 files changed