Remove suppressions for WebKit Linux bot as it is gone.

TBR=jyasskin@chromium.org
BUG=176621, 176616, 309477

Review URL: https://codereview.chromium.org/1847473002

Cr-Commit-Position: refs/heads/master@{#383914}

tools/valgrind/memcheck/suppressions.txt

@@ -1834,29 +1834,6 @@
    ...
    fun:_ZN18ValueStoreFrontend*
 }
-{
-   bug_176616_a
-   Memcheck:Uninitialized
-   fun:_ZN13WebTestRunner16WebTestProxyBase19didCreateDataSourceEPN5blink8WebFrameEPNS1_13WebDataSourceE
-   fun:_ZN13WebTestRunner12WebTestProxyI11WebViewHostP9TestShellE19didCreateDataSourceEPN5blink8WebFrameEPNS5_13WebDataSourceE
-   fun:_ZN5blink21FrameLoaderClientImpl20createDocumentLoaderERKN7blink15ResourceRequestERKNS1_14SubstituteDataE
-   fun:_ZN5blink11FrameLoader4initEv
-   fun:_ZN5blink5Frame4initEv
-   fun:_ZN5blink12WebFrameImpl21initializeAsMainFrameEPN7blink4PageE
-   fun:_ZN5blink11WebViewImpl19initializeMainFrameEPNS_14WebFrameClientE
-   fun:_ZN9TestShell15createNewWindowERKN5blink6WebURLEP16DRTDevToolsAgentPN13WebTestRunner17WebTestInterfacesE
-   fun:_ZN9TestShell16createMainWindowEv
-   fun:_ZN9TestShell10initializeEP25MockWebKitPlatformSupport
-}
-{
-   bug_176616_b
-   Memcheck:Uninitialized
-   fun:_ZN13WebTestRunner10TestRunner5resetEv
-   fun:_ZN13WebTestRunner14TestInterfaces8resetAllEv
-   fun:_ZN13WebTestRunner17WebTestInterfaces8resetAllEv
-   fun:_ZN9TestShell19resetTestControllerEv
-   fun:_ZL7runTestR9TestShellR10TestParamsRKSsb
-}
 {
    bug_176619_a
    Memcheck:Uninitialized
@@ -1878,16 +1855,6 @@
    fun:_ZN5blink12TextTrackCue22createCueRenderingTreeEv
    fun:_ZN5blink12TextTrackCue17updateDisplayTreeEf
 }
-{
-   bug_176621
-   Memcheck:Leak
-   fun:_Znw*
-   fun:_ZN13WebTestRunner10TestPlugin6createEPN5blink8WebFrameERKNS1_15WebPluginParamsEPNS_15WebTestDelegateE
-   fun:_ZN13WebTestRunner16WebTestProxyBase12createPluginEPN5blink8WebFrameERKNS1_15WebPluginParamsE
-   fun:_ZN13WebTestRunner12WebTestProxyI11WebViewHostP9TestShellE12createPluginEPN5blink8WebFrameERKNS5_15WebPluginParamsE
-   fun:_ZN5blink21FrameLoaderClientImpl12createPluginERKN7blink7IntSizeEPNS1_17HTMLPlugInElementERKNS1_4KURLERKN3WTF6VectorINSA_6String*
-   fun:_ZN5blink14SubframeLoader10loadPluginEPNS_22HTMLPlugInImageElementERKNS_4KURLERKN3WTF6StringERKNS6_6VectorIS7*
-}
 {
    bug_176891a
    Memcheck:Leak
@@ -2222,17 +2189,6 @@
    fun:_ZN5blink34CanvasRenderingContext2DV8InternalL18getImageDataMethodERKN2v820FunctionCallbackInfoINS1_5ValueEEE
    fun:_ZN5blink34CanvasRenderingContext2DV8InternalL26getImageDataMethodCallbackERKN2v820FunctionCallbackInfoINS1_5ValueEEE
 }
-{
-   bug_309477
-   Memcheck:Uninitialized
-   fun:_ZN13WebTestRunner11EventSender5resetEv
-   fun:_ZN13WebTestRunner14TestInterfaces26resetTestHelperControllersEv
-   fun:_ZN13WebTestRunner14TestInterfaces8resetAllEv
-   ...
-   fun:_ZN7content26ShellRenderProcessObserver17WebKitInitializedEv
-   fun:_ZN7content16RenderThreadImpl23EnsureWebKitInitializedEv
-   fun:_ZN7content16RenderThreadImpl15OnCreateNewViewERK18ViewMsg_New_Params
-}
 {
    bug_317166
    Memcheck:Leak