Add timing of bitcode parser to Subzero.

Add timing of bitcode parser to Subzero.

Adds timers to each bitcode block parser in Subzero, to get a reading
on how much time is used by the bitcode parser.

BUG=None
R=jvoung@chromium.org, stichnot@chromium.org

Committed: https://gerrit.chromium.org/gerrit/gitweb?p=native_client/pnacl-subzero.git;a=commit;h=58455876adbd0fc92815bb0e2419363d569df2a5

[Karl, 2014-11-03 18:33:56]

kschimpf@google.com changed reviewers:
+ jvoung@chromium.org, stichnot@chromium.org

[jvoung (off chromium), 2014-11-03 19:18:43]

lgtm

[Jim Stichnoth, 2014-11-03 19:26:31]

LGTM.

It would be nice if the timer could be lifted into the base class as a protected
member, but I can't see a clean way of initializing it in the subclass ctor
without adding an ugly timer tag argument to the superclass ctors.

[Karl, 2014-11-03 19:29:48]

Committed patchset #2 (id:20001) manually as
58455876adbd0fc92815bb0e2419363d569df2a5 (presubmit successful).