MIPS64: Fix memory allocation when code range is used for LO space only.

MIPS64: Fix memory allocation when code range is used for LO space only.

Allocation must respect requested reserve size, not requested commit area size.

Additionally fix check failures in debug mode for mips64.
After CL: https://codereview.chromium.org/1147503002/
memory for large code objects is allocated from code range,
memory for regular code objects is allocated normally.

TEST=cctest/test-spaces/MemoryChunk
BUG=

Committed: https://crrev.com/a5b0a3e298c9e8eb5917040c6f7ed2f0b919b123
Cr-Commit-Position: refs/heads/master@{#28995}

[dusmil.imgtec, 2015-06-10 13:26:44]

dusan.milosavljevic@imgtec.com changed reviewers:
+ erikcorry@chromium.org, hpayer@chromium.org, jkummerow@chromium.org,
paul.lind@imgtec.com, ulan@chromium.org

[Hannes Payer (out of office), 2015-06-11 01:46:29]

Instead of adding the MIPS defs everywhere, can we make the check valid instead?

[dusmil.imgtec, 2015-06-11 12:31:51]

Yes, I do not like them either. PTAL.

[Hannes Payer (out of office), 2015-06-12 05:16:43]

lgtm

[dusmil.imgtec, 2015-06-12 10:59:48]

The CQ bit was checked by dusan.milosavljevic@imgtec.com

[commit-bot: I haz the power, 2015-06-12 10:59:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1172333002/20001

[commit-bot: I haz the power, 2015-06-12 11:42:11]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-06-12 11:42:29]

Patchset 2 (id:??) landed as
https://crrev.com/a5b0a3e298c9e8eb5917040c6f7ed2f0b919b123
Cr-Commit-Position: refs/heads/master@{#28995}