dalvik/vm: Dalvik startup with a low memory footprint

Initialize concurrentStartBytes and createMspace using HEAP_MIN_FREE.
This helps save Android framework memory after boot.

This is for low memory targets only(~512MB RAM & hdpi resolution)
Also, set TARGET_ARCH_LOWMEM in the BoardConfig.mk file of a device
for this patch to take effect.

Conflicts:
	vm/alloc/HeapSource.cpp

Change-Id: I251dfe3d36c5085de48c8d3defd0e8709eeb678b