Refactor and optimize memory region bit functions

Move optimized bit reading from FieldEncoding to MemoryRegion,
added optimized StoreBits to MemoryRegion.

Compilation of a large app on host:
Before:
Time -j1: 31.897s
2.00% art::MemoryRegion::StoreBits(unsigned long, unsigned int, unsigned long)

After:
Time -j1: 29.620s
0.39% art::MemoryRegion::StoreBits(unsigned long, unsigned int, unsigned long)

Bug: 34621054

Test: test-art-host

Change-Id: I0509613da83cc5741d5cfada3f8a8af503784e9e