- Previously when going from unsuppressed -> suppressed we cleared certan caches
- This meant that when going from suppressed -> unsuppressed we were always re compiling every razor file
- Now instead, we produce nothing *until* the generator is unsuppressed, after which we just say that whatever is in the caches is up to date if we're suppressed.
- This ensures no downstream processing takes place when the generator is suppressed, but there is still data to incrementally update when unsuppressed
- We still remove the generated files at the last step when suppressed, so there is no output, but don't have to recompile anything to get the output back again.

…talValueProviderExtensions.cs

Co-authored-by: Jan Jones <jan.jones.cz@gmail.com>