Call ctx.InstallFile for uninstallable cc modules

SkipInstall is actually primarily used to prevent making a module
visible to Make, rename it and add new SkipInstall that actually
skips installation without affecting Make.

Call c.SkipInstall() for uninstallable cc modules to allow calling
c.installer.install, which will collect PackagingSpecs for
uninstallable cc modules, allowing them to be used by genrules.

Bug: 124313442
Test: m checkbuild
Change-Id: I8038ed5c6f05c989ac21ec06c4552fb3136b9a7a