Suppress an Windows internal/benign data race when using _vsprintf_p

tools/valgrind/tsan/suppressions.txt

 # There are a few kinds of suppressions in this file.
 # 1. third party stuff we have no control over
 #
 # 2. intentional unit test errors, or stuff that is somehow a false positive
 # in our own code, or stuff that is so trivial it's not worth fixing
 #
 # 3. Suppressions for real chromium bugs that are not yet fixed.
 # These should all be in chromium's bug tracking system (but a few aren't yet).
 # Periodically we should sweep this file and the bug tracker clean by
 # running overnight and removing outdated bugs/suppressions.
@@ skipping 971 matching lines @@
 {
    bug_132230b
    ThreadSanitizer:Race
    fun:ShellIntegration::DefaultWebClientWorker::ExecuteSetAsDefault
    fun:base::internal::RunnableAdapter::Run
 }
 {
    bug_137701
    ThreadSanitizer:Race
    ...
+   fun:_output_*
    fun:_vsnprintf_helper
-   ...
-   fun:disk_cache::BackendImpl::SyncInit
-   fun:disk_cache::BackendIO::ExecuteBackendOperation
-   fun:base::internal::RunnableAdapter::Run
 }
 {
    bug_137973_a
    ThreadSanitizer:Race
    fun:media::Pipeline::OnVideoTimeUpdate
    fun:base::internal::RunnableAdapter::Run
 }
 {
   bug_137973_b
   ThreadSanitizer:Race
@@ skipping 15 matching lines @@
    ...
    fun:testing::internal::UntypedFunctionMockerBase::UntypedInvokeWith
    fun:testing::internal::FunctionMockerBase::InvokeWith
    fun:testing::internal::FunctionMocker::Invoke
    fun:browser_sync::NewNonFrontendDataTypeControllerMock::RecordUnrecoverableError
    fun:browser_sync::::NewNonFrontendDataTypeControllerFake::RecordUnrecoverableError
    fun:browser_sync::NonFrontendDataTypeController::StartFailed
    fun:browser_sync::NewNonFrontendDataTypeController::StartAssociationWithSharedChangeProcessor
    fun:base::internal::RunnableAdapter::Run
 }