X87: fix the Sqrt issue.

X87:  fix the Sqrt issue.

   The test mjsunit/regress/regress-sqrt compares the result of Math.sqrt function
   when using full-compiler and crankshaft compiler seperately. But according to
   glibc bug fixing(https://sourceware.org/bugzilla/show_bug.cgi?id=14032). The
   glibc implementation of std::sqrt() (It is invoked in the generated code when
   full-compiler is used.) will change since glibc 2.19.

   In order to keep consistence of Math.sqrt translation in crankshaft compiler
   and the pass of mjsunit/regress/regress-sqrt. we translate the Math.sqrt func
   by calling the runtime function.

BUG=

[chunyang.dai, 2014-09-29 02:54:57]

WL.
PTAL.
thanks

[chunyang.dai, 2014-09-29 08:32:03]

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

[Weiliang, 2014-09-29 08:37:44]

lgtm

[Weiliang, 2014-09-29 08:39:49]

Committed as r24271