X87: [compiler] Remove broken support for undetectable strings.

X87: [compiler] Remove broken support for undetectable strings.

port b62dbf1efdec68ae709b0e91d3b7c13171b720c9 (r30132).

original commit messge:

    Support for undetectable strings was officially dropped in
    https://codereview.chromium.org/916753002, but the compilers
    weren't fixed properly.

BUG=

Committed: https://crrev.com/8eeec89b9fee1b268140c6a1c121d6a97339f856
Cr-Commit-Position: refs/heads/master@{#30156}

[chunyang.dai, 2015-08-13 06:29:55]

chunyang.dai@intel.com changed reviewers:
+ weiliang.lin@intel.com

[chunyang.dai, 2015-08-13 06:29:55]

PTAL

[Weiliang, 2015-08-13 12:58:41]

The CQ bit was checked by weiliang.lin@intel.com

[Weiliang, 2015-08-13 12:58:42]

lgtm

[commit-bot: I haz the power, 2015-08-13 12:58:45]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1287173002/1
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1287173002/1

[commit-bot: I haz the power, 2015-08-13 13:32:02]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-08-13 13:32:14]

Patchset 1 (id:??) landed as
https://crrev.com/8eeec89b9fee1b268140c6a1c121d6a97339f856
Cr-Commit-Position: refs/heads/master@{#30156}