[Windows build perf] _CompileAppManifest is always executed

[emaf]

Steps to Reproduce

_CompileAppManifest should be skipped if the related imput files did not change, not just because the time it takes to execute this target, but because it also causes _CoreCompileImageAssets, _CoreCompileCoreMLModels and CopyResourcesToBundle to run unnecesarily. This might not add a lot of time on local builds, but on remote builds this could add easily 3-4 seconds.

How other targets are forced to be executed:

Expected Behavior

Actual Behavior

Environment

Version information

Build Logs

Example Project (If Possible)

[rolfbjarne]

_CompileAppManifest should be skipped if the related imput files did not change

This task is a bit more complicated, because the CompileAppManifest needs to execute even if there's no input files, because we write out some default values in the resulting Info.plist in that case.

not just because the time it takes to execute this target, but because it also causes _CoreCompileImageAssets, _CoreCompileCoreMLModels and CopyResourcesToBundle to run unnecesarily.

This might be avoided by not writing out a file if the new contents is identical to the old file (so the timestamp doesn't change).