Bug 1521334, make parser to flush its tree operation queue sooner, r=hsivonen

modules/libpref/init/StaticPrefList.h

@@ -561,7 +561,7 @@ VARCACHE_PREF(
 VARCACHE_PREF(
   "html5.flushtimer.initialdelay",
    html5_flushtimer_initialdelay,
-  RelaxedAtomicInt32, 120
+  RelaxedAtomicInt32, 16
 )
 
 // Time in milliseconds between the time a network buffer is seen and the timer
@@ -569,7 +569,7 @@ VARCACHE_PREF(
 VARCACHE_PREF(
   "html5.flushtimer.subsequentdelay",
    html5_flushtimer_subsequentdelay,
-  RelaxedAtomicInt32, 120
+  RelaxedAtomicInt32, 16
 )
 
 //---------------------------------------------------------------------------