[turbofan] Re-separate logic for LET and CONST in BuildVariableAssignment

[turbofan] Re-separate logic for LET and CONST in BuildVariableAssignment

The structure of this code changed in https://codereview.chromium.org/2201193004,
but the structural changes were not essential to that CL's purpose (which was
to use Variable::binding_needs_init() consistently to decide whether to
hole-check). Now the code should appear as it did before that change, but with
the addition of binding_needs_init() checks.

R=bmeurer@chromium.org, mstarzinger@chromium.org

Committed: https://crrev.com/b028e64b27a5ccbe69b1f4516650b1584ba9abfb
Cr-Commit-Position: refs/heads/master@{#38638}

[Michael Starzinger, 2016-08-12 11:05:42]

LGTM. Thanks!

[adamk, 2016-08-15 17:35:19]

The CQ bit was checked by adamk@chromium.org

[commit-bot: I haz the power, 2016-08-15 17:35:21]

CQ is trying da patch. Follow status at
 
https://chromium-cq-status.appspot.com/v2/patch-status/codereview.chromium.or...

[commit-bot: I haz the power, 2016-08-15 18:07:45]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-08-15 18:08:16]

Description was changed from

==========
[turbofan] Re-separate logic for LET and CONST in BuildVariableAssignment

The structure of this code changed in
https://codereview.chromium.org/2201193004,
but the structural changes were not essential to that CL's purpose (which was
to use Variable::binding_needs_init() consistently to decide whether to
hole-check). Now the code should appear as it did before that change, but with
the addition of binding_needs_init() checks.

R=bmeurer@chromium.org, mstarzinger@chromium.org
==========

to

==========
[turbofan] Re-separate logic for LET and CONST in BuildVariableAssignment

The structure of this code changed in
https://codereview.chromium.org/2201193004,
but the structural changes were not essential to that CL's purpose (which was
to use Variable::binding_needs_init() consistently to decide whether to
hole-check). Now the code should appear as it did before that change, but with
the addition of binding_needs_init() checks.

R=bmeurer@chromium.org, mstarzinger@chromium.org

Committed: https://crrev.com/b028e64b27a5ccbe69b1f4516650b1584ba9abfb
Cr-Commit-Position: refs/heads/master@{#38638}
==========

[commit-bot: I haz the power, 2016-08-15 18:08:17]

Patchset 1 (id:??) landed as
https://crrev.com/b028e64b27a5ccbe69b1f4516650b1584ba9abfb
Cr-Commit-Position: refs/heads/master@{#38638}