Revert of Test262 roll (patchset #9 id:160001 of https://codereview.chromium.org/1268553003/ )

Reason for revert:
[Sheriff] Lacks one test expectation for
http://build.chromium.org/p/client.v8/builders/V8%20Linux64/builds/4573
http://build.chromium.org/p/client.v8/builders/V8%20Linux%20-%20arm64%20-%20sim/builds/4516

64 bits only?

Original issue's description:
> Update to latest test262 from 2015-07-31
>
> Committed: https://crrev.com/722ad6923887d367f14588f5ccd6697b8684bd28
> Cr-Commit-Position: refs/heads/master@{#30052}

TBR=adamk@chromium.org,littledan@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true

Review URL: https://codereview.chromium.org/1280903002

Cr-Commit-Position: refs/heads/master@{#30055}

test/test262-es6/testcfg.py

@@ -39,8 +39,8 @@ from testrunner.local import utils
 from testrunner.objects import testcase
 
 # The revision hash needs to be 7 characters?
-TEST_262_ARCHIVE_REVISION = "258d212"  # This is the 2015-07-31 revision.
-TEST_262_ARCHIVE_MD5 = "a9b26e19ce582492642af973c8cee826"
+TEST_262_ARCHIVE_REVISION = "c6ac390"  # This is the 2015-07-06 revision.
+TEST_262_ARCHIVE_MD5 = "e1393ef330f38e9cb1bfa4e3eada5ba8"
 TEST_262_URL = "https://github.com/tc39/test262/tarball/%s"
 TEST_262_HARNESS_FILES = ["sta.js", "assert.js"]