Delete the suppression for bug 83566, which seems to be fixed.

tools/valgrind/memcheck/suppressions.txt

Index: tools/valgrind/memcheck/suppressions.txt
===================================================================
--- tools/valgrind/memcheck/suppressions.txt	(revision 151244)
+++ tools/valgrind/memcheck/suppressions.txt	(working copy)
@@ -3068,20 +3068,6 @@
    fun:_ZN15WebContentsImpl15NavigateToEntryERKN7content19NavigationEntryImplENS0_20NavigationController10ReloadTypeE
 }
 {
-   bug_83566
-   Memcheck:Unaddressable
-   fun:_ZN7WebCore*V8Entr*Callback11handleEvent*
-   ...
-   fun:_ZN6WebKit31WorkerFileSystemCallbacksBridge21runTaskOnWorkerThreadEPN7WebCore22ScriptExecutionContextEN3WTF10PassRefPtrIS0_EENS4_10PassOwnPtrINS2_4TaskEEE
-   fun:_ZN7WebCore16CrossThreadTask2IN3WTF10PassRefPtrIN6WebKit31WorkerFileSystemCallbacksBridgeEEES5_NS1_10PassOwnPtrINS_22ScriptExecutionContext4TaskEEES9_E11performTaskEPS7_
-   fun:_ZN7WebCore13WorkerRunLoop4Task11performTaskEPNS_22ScriptExecutionContextE
-   fun:_ZN7WebCore13WorkerRunLoop9runInModeEPNS_13WorkerContextERKNS_13ModePredicateE
-   fun:_ZN7WebCore13WorkerRunLoop3runEPNS_13WorkerContextE
-   fun:_ZN7WebCore12WorkerThread12runEventLoopEv
-   fun:_ZN7WebCore21DedicatedWorkerThread12runEventLoopEv
-   fun:_ZN7WebCore12WorkerThread12workerThreadEv
-}
-{
    bug_83609
    Memcheck:Leak
    fun:_Znw*