Split core_current into separate module specific APIs

Instead of creating core_current stubs directly from the source for
libcore, ICU and conscrypt this creates separate stubs libraries for
each and then creates the core_current by combining them together.

The new stubs libraries are named after the mainline module to which
they belong.

Test: m checkbuild
Bug: 141613583
Change-Id: I0f84ba5c5ed3754cbbeb7761523fc6b7a9681359
1 file changed