CacheRemoveHandler can't run in same op as remove of parent cache-container

CacheRemoveHandler tries to read its parent resource in Stage.RUNTIME, which means it can't run in the same op (say a composite) with a remove of the parent, as the parent resource will be gone by RUNTIME.

This will also interfere with the WFCORE-808 improvement.

Easy fix, as the read of the parent resource looks to be cruft; the data is never used.