Delay eval to save memory use in create-suite-dependencies

Instead of passing the entire contents of
$(COMPATIBILITY.$(suite).FILES) to eval, which may keep that string
around, delay the evaluation of that, and the new files until inside the
eval.

This saves ~2.8GB: 7.4GB -> 4.6GB of ckati max resident memory for a
relatively small internal build. It also saves ~10% of the makefile
loading time (81 -> 73 seconds).

Test: build-aosp_arm.ninja is identical
Change-Id: If45a4796f1bbf6d67dff388ea877a6115a4e06f4