Revert of exclude PhishingDOMFeatureExtractorTest.* browser_tests on Dr....

Revert of exclude PhishingDOMFeatureExtractorTest.* browser_tests on Dr. Memory bots (patchset #1 id:1 of https://codereview.chromium.org/1371193003/ )

Reason for revert:
I'm reverting the relevant CL, https://codereview.chromium.org/1373993002/

so this exclusion is no longer necessary.

Original issue's description:
> exclude PhishingDOMFeatureExtractorTest.* browser_tests on Dr. Memory bots
>
> TBR=erikchen@chromium.org
> BUG=536891
> NOTRY=true
>
> Committed: https://crrev.com/2b4bfec5eab7ab8986557934ef9bd27e87c8e22b
> Cr-Commit-Position: refs/heads/master@{#351107}

TBR=zhaoqin@chromium.org
NOPRESUBMIT=true
NOTREECHECKS=true
NOTRY=true
BUG=536891

Review URL: https://codereview.chromium.org/1375743002

Cr-Commit-Position: refs/heads/master@{#351129}

tools/valgrind/gtest_exclude/browser_tests.gtest-drmemory.txt

@@ -78,6 +78,3 @@ PDFExtensionTest.WhitespaceTitle
 
 # https://crbug.com/530729
 SiteDetailsBrowserTest.ManyCrossSiteIframes
-
-# https://crbug.com/536891
-PhishingDOMFeatureExtractorTest.*