Reg utility fix

Long ago in a galaxy far away, there was a trace compiler that
handled short code fragments with a small, sparse and variable
set of temp registers.  In that situation, doing linear reg
lookups wasn't terrible.  In the new world that has a fixed and
packed set of registers, a linear search is unnecessary, foolish
and wasteful.  [P.S. perf showed that roughly 25% of all
compilation time was spent doing register manipulation!]

Change-Id: I6f23d9f70367fb4139cc28a27fd9fdf8beffa270
4 files changed
tree: 1706bf3e0bbdb9f7a704140f70011c1b362fa294
  2. build/
  3. oat_process/
  4. oat_runtime/
  5. src/
  6. test/
  7. tools/