Disable RtcEventLogTest.DropOldEvents on DrMemory.

BUG=webrtc:5312
R=terelius@webrtc.org

Review URL: https://codereview.webrtc.org/1495093004 .

Cr-Commit-Position: refs/heads/master@{#10894}
diff --git a/tools/valgrind-webrtc/gtest_exclude/video_engine_tests.gtest-drmemory_win32.txt b/tools/valgrind-webrtc/gtest_exclude/video_engine_tests.gtest-drmemory_win32.txt
index ac2a995..37c32ef 100644
--- a/tools/valgrind-webrtc/gtest_exclude/video_engine_tests.gtest-drmemory_win32.txt
+++ b/tools/valgrind-webrtc/gtest_exclude/video_engine_tests.gtest-drmemory_win32.txt
@@ -16,3 +16,5 @@
 EndToEndTest.AssignsTransportSequenceNumbers
 # Flaky: https://bugs.chromium.org/p/webrtc/issues/detail?id=5225
 BitrateEstimatorTest.SwitchesToASTThenBackToTOFForVideo
+# https://bugs.chromium.org/p/webrtc/issues/detail?id=5312
+RtcEventLogTest.DropOldEvents