web_tests: Re-enable test

Re-enable
  svg/animations/mpath-remove-from-dependents-on-delete-crash.html

This is likely fixed now.

Bug: 874442
Change-Id: I2ce2980fd59fab1b9951c4aa34b942c8645e080b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1774620Reviewed-by: Kentaro Hara <haraken@chromium.org>
Commit-Queue: Michael Lippautz <mlippautz@chromium.org>
Cr-Commit-Position: refs/heads/master@{#691523}

third_party/blink/web_tests/LeakExpectations

@@ -56,9 +56,6 @@ crbug.com/848354 [ Linux ] plugins/fullscreen-plugins-dont-reload.html [ Pass Le
 # Test flaking on Linux Trusty Leak
 crbug.com/862029 [ Linux ] http/tests/devtools/tracing/timeline-misc/timeline-window-filter.js [ Pass Leak ]
 
-# Sheriff 2018-08-15
-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 Leak ]
 crbug.com/847114 [ Linux ] virtual/threaded/http/tests/devtools/tracing/decode-resize.js [ Pass Failure Leak ]