Add "//apex_available:platform" to apex_available.

When specifying apex_availabe, "//apex_available:platform" needs to be
included explicitly to allow non-apex modules to access the module.

Bug: 153022187
Bug: 152762638
Test: build
Change-Id: Ic505bb04f8ce4b12d65142ed368af9d10ff3179e
2 files changed