Adjust leak suppression for decode-resize.js

Example failure:
https://ci.chromium.org/p/chromium/builders/ci/WebKit%20Linux%20Leak/3490

TBR=caseq@chromium.org

Bug: 847114
Change-Id: I2ebf3486557e74d94e0eb7f0fd2e73ab10f84ad7
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1764671Reviewed-by: Evan Stade <estade@chromium.org>
Cr-Commit-Position: refs/heads/master@{#689222}

third_party/blink/web_tests/LeakExpectations

@@ -66,8 +66,8 @@ crbug.com/862029 [ Linux ] http/tests/devtools/tracing/timeline-misc/timeline-wi
 crbug.com/874442 [ Linux ] svg/animations/mpath-remove-from-dependents-on-delete-crash.html [ Pass Crash ]
 
 # Sheriff 2018-08-17
-crbug.com/847114 [ Linux ] http/tests/devtools/tracing/decode-resize.js [ Pass Failure ]
-crbug.com/847114 [ Linux ] virtual/threaded/http/tests/devtools/tracing/decode-resize.js [ Pass Failure ]
+crbug.com/847114 [ Linux ] http/tests/devtools/tracing/decode-resize.js [ Pass Failure Leak ]
+crbug.com/847114 [ Linux ] virtual/threaded/http/tests/devtools/tracing/decode-resize.js [ Pass Failure Leak ]
 
 # Sheriff 2018-08-29
 crbug.com/878724 [ Linux ] editing/selection/modify_extend/extend_by_character.html [ Pass Leak ]