[turbofan] Some cleanup to the Typer.

[turbofan] Some cleanup to the Typer.

This change does the following:

  a.) Remove unused fields from the Typer.
  b.) Move some interesting unions to types.h.
  c.) Reduce Typer constructor overhead.
  d.) Avoid heap allocation in the Typer.

R=jarin@chromium.org

Committed: https://crrev.com/def2411a29b4796f0784462a200193c1305382a8
Cr-Commit-Position: refs/heads/master@{#29178}

[Benedikt Meurer, 2015-06-22 08:09:16]

Hey Jaro,

Here's some more cleanup for the Typer.
Please take a look.

Thanks,
Benedikt

[Jarin, 2015-06-22 08:30:07]

lgtm

[Benedikt Meurer, 2015-06-22 09:14:21]

The CQ bit was checked by bmeurer@chromium.org

[commit-bot: I haz the power, 2015-06-22 09:14:30]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1199903002/1

[commit-bot: I haz the power, 2015-06-22 09:15:58]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-06-22 09:16:18]

Patchset 1 (id:??) landed as
https://crrev.com/def2411a29b4796f0784462a200193c1305382a8
Cr-Commit-Position: refs/heads/master@{#29178}