Roll Fuchsia SDK to bb4f07c0178ae528aeb9d284333e3d0bf59a0eb7

Notably includes
https://fuchsia.googlesource.com/magenta/+/396b28ef2039e962c19f9d972d72ed56aa665d5b
which makes the POSIX-y impl of PartitionAlloc work on Fuchsia, so
enable those tests.

TBR=wez@chromium.org

Bug: 706592, 707030
Change-Id: I81969597e87969c755afb6e538bccf5ab1cf1eb9
Reviewed-on: https://chromium-review.googlesource.com/600987Reviewed-by: Scott Graham <scottmg@chromium.org>
Reviewed-by: Wez <wez@chromium.org>
Commit-Queue: Scott Graham <scottmg@chromium.org>
Commit-Queue: Wez <wez@chromium.org>
Cr-Commit-Position: refs/heads/master@{#491825}

DEPS

@@ -1208,7 +1208,7 @@ hooks_os = {
       'action': [
         'python',
         'src/build/fuchsia/update_sdk.py',
-        '2bebd264dfe3bec89469a4179a8292b416cdf2fa',
+        'bb4f07c0178ae528aeb9d284333e3d0bf59a0eb7',
       ],
     },
   ],

testing/buildbot/filters/fuchsia.base_unittests.filter

@@ -27,27 +27,6 @@
 -LoggingTest.CheckCausesDistinctBreakpoints
 -NativeLibraryTest.LoadLibrary
 -NativeLibraryTest.LoadLibraryPreferOwnSymbols
--PartitionAllocTest.Basic
--PartitionAllocTest.DumpMemoryStats
--PartitionAllocTest.FreeCache
--PartitionAllocTest.FreePageListPageTransitions
--PartitionAllocTest.GenericAlloc
--PartitionAllocTest.GenericAllocGetSize
--PartitionAllocTest.GenericAllocSizes
--PartitionAllocTest.LostFreePagesBug
--PartitionAllocTest.MappingCollision
--PartitionAllocTest.MultiAlloc
--PartitionAllocTest.MultiPageAllocs
--PartitionAllocTest.MultiPages
--PartitionAllocTest.PageRefilling
--PartitionAllocTest.PageTransitions
--PartitionAllocTest.PartialPageFreelists
--PartitionAllocTest.PartialPages
--PartitionAllocTest.PreferActiveOverEmpty
--PartitionAllocTest.Purge
--PartitionAllocTest.PurgeDiscardable
--PartitionAllocTest.Realloc
--PartitionAllocTest.ReallocMovesCookies
 -PathServiceTest.Get
 -PersistentHistogramAllocatorTest.CreateSpareFile
 -PersistentHistogramAllocatorTest.CreateWithFile