Ingore CC prebuilts from cmake snapshots

The cmake snapshot scripts currently looks at the `cc.Module.compiler`
property to determine whether a cc_* module is a prebuilt. As part of
b/275273834. some cc_* prebuilt modules which provide APIs will have a
non-nil `compiler` to convert the API .txt file to stub .c files.

This CL updates the cmake generation script to ignore prebuilts using
the `IsPrebuilt` function rather than `cc.Module.compiler`

Bug: 275273834
Test: m nothing --no-skip-soong-tests
Change-Id: Id8ba22b1c5ad13fb31e75a407a25e97a8040d0b1