GC triggering performance optimizations

Copy the correct starting heap size at process init.
Interfaces to set GC/managed heap parameters.

Change-Id: If0b1637291e77f9781ae6249c5d0257f659253ca
BUILD_PREBUILT host libjavacore

Change-Id: I051ff33a86853887e9937827b51146be2290073d

Conflicts:
	NativeCode.mk
BUILD_PREBUILT target libjavacore

Change-Id: Id2676ff2d7cb1caebc9ec91ccfdbc272ba622384

Conflicts:
	NativeCode.mk
NativeCode: fix libjavacore LOCAL_MODULE_STEM

Change-Id: I9a72da40963a7bca2d6e56726b5b0faa2b8db8cf
update libjavacore prebuilts