Evaluate the need for _GenerateTestingPlatformEntryPointFileInputCache and _GenerateSelfRegisteredExtensionsFileInputCache

[Youssef1313]

I'm guessing these two targets are no longer needed. They probably existed historically because of previously using the wrong hook of CoreCompile instead of BeforeCompile which was fixed in #4777.

There is already a _GenerateCompileDependencyCache target which will include the generated files now that we are correctly hooking into BeforeCompile. So feels like both targets are no longer needed?

[Evangelink]

@MarcoRossignoli to confirm

[MarcoRossignoli]

Verify with the binlog that when we run the second time we're not re-generating the sources, if so let's cleanup.

[Youssef1313]

Not double checked, but thinking about it again, I think we need it. Closing for now