Add ETL flags for ReadyToRun (#15801)

Add ETL flags for ReadyToRun (#15801)

Add flags to track the presence of ReadyToRun codegen in an assembly
and module.

Add jitting flags to indicate when a method is jitted because the
precompiled code was rejected, either by a profiler or by ReadyToRun
dependence tracking.

Together these can be used to distingish between
* methods jitted because their assemblies were not precompiled
* methods jitted because they were not precompiled in an otherwise
precompiled assembly