Remove uninit read suppression for Mojo EDK writes

tools/valgrind/drmemory/suppressions_full.txt

 # This file contains suppressions for the Dr.Memory tool, see
 # http://dev.chromium.org/developers/how-tos/using-drmemory
 #
 # This file should contain suppressions only for the reports happening
 # in the 'full' mode (drmemory_full).
 # For the reports that can happen in the light mode (a.k.a. drmemory_light),
 # please use suppressions.txt instead.
 
 ###############################################################
 # Known reports on the third party we have no control over.
@@ skipping 1679 matching lines @@
 
 UNINITIALIZED READ
 name=bug_399293
 blink_web.dll!blink::InputMethodController::extendSelectionAndDelete
 blink_web.dll!blink::WebLocalFrameImpl::extendSelectionAndDelete
 content.dll!content::RenderFrameImpl::OnExtendSelectionAndDelete
 *!content::RenderViewImplTest_OnExtendSelectionAndDelete_Test::TestBody
 *!testing::internal::HandleExceptionsInMethodIfSupported<>
 
 UNINITIALIZED READ
-name=bug_398547
-system call NtWriteFile parameter #5
-KERNELBASE.dll!WriteFile
-KERNEL32.dll!WriteFile
-mojo_system_impl.dll!mojo::edk::`anonymous namespace'::ChannelWin::WriteNoLock
-
-UNINITIALIZED READ
 name=bug_399842
 skia.dll!S32A_Opaque_BlitRow32_SSE4
 
 HANDLE LEAK
 name=bug_403544
 system call NtCreateSemaphore
 KERNELBASE.dll!CreateSemaphoreExW
 ...
 v8.dll!v8::internal::SweeperThread::SweeperThread
 ...
@@ skipping 445 matching lines @@
 content.dll!content::ChildThreadImpl::Init
 content.dll!content::ChildThreadImpl::ChildThreadImpl
 content.dll!content::UtilityThreadImpl::UtilityThreadImpl
 content.dll!content::UtilityMain
 
 UNADDRESSABLE ACCESS
 name=bug_617740
 media.dll!mkvmuxer::Segment::WriteFramesAll
 media.dll!mkvmuxer::Segment::Finalize
 media.dll!media::WebmMuxer::~WebmMuxer