ARM: Try to emit branches early to save memory.

Try to emit unexpanded branches when binding a Label to
reduce the memory needed for Fixup dependencies. We use
a simple heuristic to limit the time we spend trying
but this heuristic is enough to resolve all branches in
the emitted String.equals() intrinsic.

Test: Run ART test suite on host and Nexus 6.
Test: Manually check memory usage for a certain apk.
Bug: 28603175
Change-Id: I362e07c2c1285ff609cf8df0a00b6b420729b9ce