Reland "Disable core.stacktrace_unittest.TabStackTraceTest.testValidDump on win"

This reverts commit 69141da0.

Reason for revert: core.stacktrace_unittest.TabStackTraceTest.testValidDump is failing on Win 7, disabling this test for now. 

Original change's description:
> Revert "Disable core.stacktrace_unittest.TabStackTraceTest.testValidDump on win"
> 
> This reverts commit 216e6d16.
> 
> Reason for revert: culrpit CL was reverted 
> 
> BUG:chromium:846313
> 
> Original change's description:
> > Disable core.stacktrace_unittest.TabStackTraceTest.testValidDump on win
> > 
> > TBR=kbr@chromium.org
> > NOTRY=true  # net_unittests flake
> > 
> > Bug: 846289
> > Change-Id: I7fa42786ebdb448fd424e37a7c777e60df6b3c36
> > Reviewed-on: https://chromium-review.googlesource.com/1071868
> > Commit-Queue: Ned Nguyen <nednguyen@google.com>
> > Reviewed-by: Ned Nguyen <nednguyen@google.com>
> > Cr-Commit-Position: refs/heads/master@{#561594}
> 
> TBR=nednguyen@google.com
> 
> Change-Id: Ibf328d3ea480b094e47c5037a7498f198ef94e62
> No-Presubmit: true
> No-Tree-Checks: true
> No-Try: true
> Bug: 846289
> Reviewed-on: https://chromium-review.googlesource.com/1073091
> Commit-Queue: Ned Nguyen <nednguyen@google.com>
> Reviewed-by: Ned Nguyen <nednguyen@google.com>
> Cr-Commit-Position: refs/heads/master@{#561881}

TBR=nednguyen@google.com

Change-Id: I039a5ffa03afbd50d79c57529d1b561def58ccdf
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 846289
Reviewed-on: https://chromium-review.googlesource.com/1073492Reviewed-by: Luna Lu <loonybear@chromium.org>
Commit-Queue: Luna Lu <loonybear@chromium.org>
Cr-Commit-Position: refs/heads/master@{#561933}

tools/perf/core/stacktrace_unittest.py

@@ -16,6 +16,7 @@ class TabStackTraceTest(tab_test_case.TabTestCase):
   # disabled shortly so just disable it for now.
   # All platforms except chromeos should at least have a valid minidump.
   @decorators.Disabled('snowleopard', 'chromeos')
+  @decorators.Disabled('win')  # crbug.com/846313
   def testValidDump(self):
     with self.assertRaises(exceptions.DevtoolsTargetCrashException) as c:
       self._tab.Navigate('chrome://crash', timeout=5)