Convert float64 to float32 when coerced with a heapf32 assignment.

Convert float64 to float32 when coerced with a heapf32 assignment.

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=mjsunit/asm-wasm
R=titzer@chromium.org,aseemgarg@chromium.org
LOG=N

Committed: https://crrev.com/2a9a770c2a1bde809c18f749a19b6a5f75f0ce5c
Cr-Commit-Position: refs/heads/master@{#34404}

[titzer, 2016-03-01 17:55:19]

lgtm

[bradn, 2016-03-01 18:04:06]

The CQ bit was checked by bradnelson@google.com

[commit-bot: I haz the power, 2016-03-01 18:04:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1749233002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1749233002/1

[commit-bot: I haz the power, 2016-03-01 18:06:30]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2016-03-01 18:07:32]

Description was changed from

==========
Convert float64 to float32 when coerced with a heapf32 assignment.

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=mjsunit/asm-wasm
R=titzer@chromium.org,aseemgarg@chromium.org
LOG=N
==========

to

==========
Convert float64 to float32 when coerced with a heapf32 assignment.

BUG= https://code.google.com/p/v8/issues/detail?id=4203
TEST=mjsunit/asm-wasm
R=titzer@chromium.org,aseemgarg@chromium.org
LOG=N

Committed: https://crrev.com/2a9a770c2a1bde809c18f749a19b6a5f75f0ce5c
Cr-Commit-Position: refs/heads/master@{#34404}
==========

[commit-bot: I haz the power, 2016-03-01 18:07:33]

Patchset 1 (id:??) landed as
https://crrev.com/2a9a770c2a1bde809c18f749a19b6a5f75f0ce5c
Cr-Commit-Position: refs/heads/master@{#34404}

[bradn, 2016-03-01 18:39:31]

lgtm