[Fuchsia] Re-enable Mojo DataPipe tests that were slow on Fuchsia/Dbg.

Bug: 831024, 814914
Change-Id: I8281b6a6538352f9d08e8e426a210a9af012b7fb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1614473
Commit-Queue: Wez <wez@chromium.org>
Commit-Queue: John Budorick <jbudorick@chromium.org>
Auto-Submit: Wez <wez@chromium.org>
Reviewed-by: John Budorick <jbudorick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661205}

testing/buildbot/filters/fuchsia.mojo_unittests.filter

@@ -7,9 +7,3 @@
 # crbug.com/780317 - These timeout under QEMU s/w emulation of ARM64.
 -MultiprocessMessagePipeTestWithPeerSupport.PingPongPipe*
 -MessagePipeTest.SharedBufferHandlePingPong
-
-# Flaky since migration to unified mojo_unittests, https://crbug.com/814914.
--FileDataPipeProducerTest.HugeFile
-
-# Flaky due to slow process launch, https://crbug.com/831024.
--DataPipeTest.SendConsumerAndCloseProducer