Revert of Put RegExp js code in strict mode

Revert of Put RegExp js code in strict mode (patchset #2 id:20001 of https://codereview.chromium.org/1776883005/ )

Reason for revert:
Found to break SAP Web IDE, and these semantics are not shipped in any other browser.
Revert to legacy semantics while assessing web compatibility.

BUG=chromium:624318
Original issue's description:
> Put RegExp js code in strict mode
> 
> src/js/regexp.js was one of the few files that was left in sloppy
> mode. The ES2017 draft specification requires that writes to
> lastIndex throw when the property is non-writable, and test262
> tests enforce this behavior. This patch puts that file in strict
> mode.
> 
> BUG=v8:4504
> R=yangguo@chromium.org
> LOG=Y
> 
> Committed: https://crrev.com/80b1b2a45bbd9bf3d08e4e6516acfaaa8f438213
> Cr-Commit-Position: refs/heads/master@{#34801}

TBR=yangguo@chromium.org
# Not skipping CQ checks because original CL landed more than 1 days ago.
BUG=v8:4504

[Dan Ehrenberg, 2016-06-29 21:40:31]

Created Revert of Put RegExp js code in strict mode

[Dan Ehrenberg, 2016-06-29 21:40:46]

littledan@chromium.org changed reviewers:
+ adamk@chromium.org

[Dan Ehrenberg, 2016-06-29 21:41:02]

Should we revert this patch?

[adamk, 2016-06-29 21:46:51]

reverting for now lgtm

[Dan Ehrenberg, 2016-06-29 21:46:54]

The CQ bit was checked by littledan@chromium.org to run a CQ dry run

[commit-bot: I haz the power, 2016-06-29 21:47:04]

Dry run: 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, 2016-06-29 21:48:34]

The CQ bit was unchecked by commit-bot@chromium.org

[commit-bot: I haz the power, 2016-06-29 21:48:35]

Dry run: Try jobs failed on following builders:
  v8_android_arm_compile_rel on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_android_arm_compile_rel/...)
  v8_linux64_avx2_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_avx2_rel_ng/buil...)
  v8_linux64_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_rel_ng/builds/8294)
  v8_linux_arm64_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel_ng/build...)
  v8_linux_arm_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm_rel_ng/builds/...)
  v8_linux_dbg_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_dbg_ng/builds/8270)
  v8_linux_gcc_compile_rel on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_gcc_compile_rel/bu...)
  v8_linux_mipsel_compile_rel on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_mipsel_compile_rel...)
  v8_linux_rel_ng on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_rel_ng/builds/8251)
  v8_presubmit on master.tryserver.v8 (JOB_FAILED,
http://build.chromium.org/p/tryserver.v8/builders/v8_presubmit/builds/18459)

[Yang, 2016-06-30 05:10:13]

On 2016/06/29 21:48:35, commit-bot: I haz the power wrote:
> Dry run: Try jobs failed on following builders:
>   v8_android_arm_compile_rel on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_android_arm_compile_rel/...)
>   v8_linux64_avx2_rel_ng on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_avx2_rel_ng/buil...)
>   v8_linux64_rel_ng on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux64_rel_ng/builds/8294)
>   v8_linux_arm64_rel_ng on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm64_rel_ng/build...)
>   v8_linux_arm_rel_ng on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_arm_rel_ng/builds/...)
>   v8_linux_dbg_ng on master.tryserver.v8 (JOB_FAILED,
> http://build.chromium.org/p/tryserver.v8/builders/v8_linux_dbg_ng/builds/8270)
>   v8_linux_gcc_compile_rel on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_gcc_compile_rel/bu...)
>   v8_linux_mipsel_compile_rel on master.tryserver.v8 (JOB_FAILED,
>
http://build.chromium.org/p/tryserver.v8/builders/v8_linux_mipsel_compile_rel...)
>   v8_linux_rel_ng on master.tryserver.v8 (JOB_FAILED,
> http://build.chromium.org/p/tryserver.v8/builders/v8_linux_rel_ng/builds/8251)
>   v8_presubmit on master.tryserver.v8 (JOB_FAILED,
> http://build.chromium.org/p/tryserver.v8/builders/v8_presubmit/builds/18459)

revert lgtm once patch applies cleanly.

[Dan Ehrenberg, 2016-06-30 14:37:22]

Committed at https://codereview.chromium.org/2112713003/