Use the empty string for the core image variant so that modules
added to imageMutator do not change their build directory.
Bug: 142286466
Test: m checkbuild
Change-Id: Ida4534d9a4d6176236aaa480fed359ce27acfaa1
Merged-In: Ida4534d9a4d6176236aaa480fed359ce27acfaa1
(cherry picked from commit 72d685ee7f45e5393be44ae4159edf083ac918de)
Move the ImageMutator to be registered just after the archMutator
in preparation for moving it between osMutator and archMutator.
Requries updating variants in a few tests that now run the
ImageMutator.
Bug: 142286466
Test: no change to build.ninja
Test: all soong tests
Change-Id: Ia9d2a7bc0e225bedec3c9a83ea04f471a931bf47
Prepare for making the image mutator available to all modules and
moving it between the os and arch mutators by moving it into the
android package and using an interface implemented by the module
types to control it.
Bug: 142286466
Test: No unexpected changes to out/soong/build.ninja
Change-Id: I0dcc9c7b5ec80edffade340c367f6ae4da34151b