[MemSheriff] Exclude failing test PEImageTest.EnumeratesPE from Dr. Memory

TBR=wfh@chromium.org
BUG=461816
NOTRY=true

Review URL: https://codereview.chromium.org/955983002

Cr-Commit-Position: refs/heads/master@{#318046}

tools/valgrind/gtest_exclude/base_unittests.gtest-drmemory_win32.txt

@@ -36,3 +36,5 @@ TraceEventTestFixture.TraceContinuousSampling
 # so we can avoid excluding this for light mode.
 MessageLoopTestTypeUI.RecursiveDenial3
 
+# crbug/461816
+PEImageTest.EnumeratesPE