Fix PaintControllerUnderInvalidationTest.MoreDrawing on official builds

Official build doesn't output strings on CHECK failures.

BUG=644768
CQ_INCLUDE_TRYBOTS=master.tryserver.chromium.linux:linux_layout_tests_slimming_paint_v2

Review-Url: https://codereview.chromium.org/2319283002
Cr-Commit-Position: refs/heads/master@{#417112}

third_party/WebKit/Source/platform/graphics/paint/PaintControllerTest.cpp

@@ -1703,7 +1703,7 @@ TEST_F(PaintControllerUnderInvalidationTest, ChangeDrawing)
 
 TEST_F(PaintControllerUnderInvalidationTest, MoreDrawing)
 {
-    EXPECT_DEATH(testMoreDrawing(), "Can't find cached display item");
+    EXPECT_DEATH(testMoreDrawing(), "");
 }
 
 TEST_F(PaintControllerUnderInvalidationTest, LessDrawing)