A64: Remove two TODOs that will not be done.

A64: Remove two TODOs that will not be done.

- For the LDP/STP TODO: The arguments need dereferencing, so using LDP/STP would
  require some additional checks.
- For the constant pools TODO: Unless we need to, there is no benefit from
  trying to generate constant pools more often, as it would likely only pollute
  the I-cache.

R=ulan@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=19316

[ulan, 2014-02-12 11:33:58]

lgtm

[Alexandre Rames, 2014-02-12 11:55:58]

Committed patchset #1 manually as r19316 (presubmit successful).