Make use of templatized convienience functions for adding Hydrogen instructions.

Make use of templatized convienience functions for adding Hydrogen instructions.

Building on the previous changes from https://codereview.chromium.org/18050004/
this patch makes even more use of the templatized functions for adding
Hydrogen instructions.

R=danno@chromium.org
BUG=

[danno, 2013-06-28 09:02:46]

I like this extension to my original patch, but for a style change of this
magnitude, we should probably get some other folks to comment and whether we
like this going forward.

[Jakob Kummerow, 2013-06-28 09:17:56]

Fine with me.

I didn't perceive the "AddInstruction(new(zone()) ...)" sequence as a pain
point, and I liked being able to search for uses of a given HInstruction's
constructor, but I guess that ship has sailed anyway. The templatized methods
are more concise, and that's definitely an upside.

[danno, 2013-06-28 11:07:09]

ok, unless there are other serious objections, lgtm

[Benedikt Meurer, 2013-06-28 11:50:09]

Committed patchset #1 manually as r15379 (presubmit successful).