ARM64: Fix and improve --trace-sim register trace.

- Use standard names (except that our GREY is the standard BLACK).
- Make non-bold colours explicit, otherwise the boldness can carry over
  into subsequent colour declarations.
- I've moved some colours around to make them consistent. Register value
  updates (which are very common) now stand out less than they did,
  making the less-common (and arguably more important) debug
  announcements appear brighter.
  - FP registers and values are now magenta.
  - Integer registers and values are now cyan.
  - Memory accesses are now blue.
- LOG_WRITE prints the source register for stores.
- Loads are logged with a format similar to that used for stores.
  Specifically, the memory address is printed alongside the new register
  value.
- Updates to D registers print the raw bits as well as the double value.
  Updates to S registers print the raw bits as well as the float value.
  (Previously, we printed both double and float interpretations of the
  bits, which was a bit cluttered.)

BUG=
R=ulan@chromium.org

Review URL: https://codereview.chromium.org/548473002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@23732 ce2b1a6d-e550-0410-aec6-3dcde31c8c00