- Renamed `RazorEditorParser` => `VisualStudioRazorParser` (maintained a copy of the original in Legacy)
- Tried to make as little changes as possible to the `BackgroundParser` due to its complexity; mostly just removed the TreeStructureChanged logic since this is re-done on the Razor editor side of things.
- Split the `RazorEditorParserTest`s into two separate tests. Partial parser tests and the VS parsing tests.
- Updated `StringTextSnapshot` to support changes in order to test the VS parser.
#1536