[turbofan] Remove bloated GraphBuilder base class.

[turbofan] Remove bloated GraphBuilder base class.

Using the GraphBuilder base class forces each node creation to go
through a virtual function dispatch just for the sake of saving the
duplication of the NewNode helper methods. In total that added up to
saving minus (sic!) six lines of code.

R=titzer@chromium.org

Committed: https://crrev.com/0788c98d3b3854cb35d3c1534ff5382824f859cf
Cr-Commit-Position: refs/heads/master@{#29799}

[Jarin, 2015-07-23 07:37:32]

jarin@chromium.org changed reviewers:
+ jarin@chromium.org

[Jarin, 2015-07-23 07:37:33]

lgtm

[Michael Starzinger, 2015-07-23 07:56:46]

The CQ bit was checked by mstarzinger@chromium.org

[commit-bot: I haz the power, 2015-07-23 07:56:50]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1252093002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1252093002/1

[commit-bot: I haz the power, 2015-07-23 08:25:34]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-07-23 08:25:50]

Patchset 1 (id:??) landed as
https://crrev.com/0788c98d3b3854cb35d3c1534ff5382824f859cf
Cr-Commit-Position: refs/heads/master@{#29799}