make CtsShim*Prebuilt available to platform

CtsShim*Prebuilt are listed in PRODUCT_PACKAGES.
They should be available to "//apex_available:platform".

Bug: 159639183
Bug: 158169437
Bug: 159392784
Test: presubmit
Merged-In: I5eec7a62e07f9d5138f7fd71268d5dd2ca2e77d4
Change-Id: I5eec7a62e07f9d5138f7fd71268d5dd2ca2e77d4
(cherry picked from commit ab9f2256)