Add flags needed to switch Jack to 1.8 for CTS targets

When linking against .jack files that contain 1.8 language
features Jack (currently) requires -D jack.java.source.version=1.8.

"core-tests" includes 1.8 language features.

core-tests-hostdex does not appear to be used in this
branch but it is used in downstream branches.

Bug: 27113322
Bug: 26953739
Change-Id: I299ac0b50f58611e4eeac97b7d578307f205cae0
1 file changed