Revert "A few more Java7 related clean ups."

This reverts commit 3aad6d5704b700fdad37d1bac0b9a45e9336fd1c.

Change-Id: I25dcabc1b320eed8fc63a7ba8f8d4b3fe314bfd2
Revert "Add experimental flag to support OpenJDK builds."

This reverts commit 606fe6706d37729f9bdd9916160c0bf890b1d8dd.

Conflicts:
	core/main.mk

Change-Id: Iac21b47e1a651dc04daa3bc2283dcc8e7790af51