reenable HTML threaded parser benchmark

This CL re-enables threaded parser microbenchmark.

The comment said there was a bug where display:none-ed <iframe> created
its LayoutObjectTree, but the bug no longer repros on current Blink.

BUG=https://bugs.webkit.org/show_bug.cgi?id=107236

Review URL: https://codereview.chromium.org/1316283003

git-svn-id: svn://svn.chromium.org/blink/trunk@201529 bbb929c8-8fbe-4397-9dbb-9b2b20218538

third_party/WebKit/PerformanceTests/Skipped

@@ -33,11 +33,6 @@ inspector
 
 Canvas/drawimage.html
 
-# Has a time-dependency (monotonically increasing), and is much slower than
-# necessary due to https://bugs.webkit.org/show_bug.cgi?id=107236
-# but is still useful for testing the threaded parser.
-Parser/html-parser-threaded.html
-
 # Redundant with chromium's page cyclers.
 Replay