[PartitionAlloc] Disable PartitionAddressSpace::UninitForTesting when...

[PartitionAlloc] Disable PartitionAddressSpace::UninitForTesting when USE_PARTITION_ALLOC_AS_MALLOC is enabled.

This causes the memory allocated before running tests. So the tests will crash because of access violation.

Bug: 998048
Change-Id: I3e91471f1d55284ea6fbd2d3045171ede017902c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2410145Reviewed-by: Kentaro Hara <haraken@chromium.org>
Reviewed-by: Bartek Nowierski <bartekn@chromium.org>
Reviewed-by: Benoit L <lizeb@chromium.org>
Commit-Queue: Takashi Sakamoto <tasak@google.com>
Cr-Commit-Position: refs/heads/master@{#807428}

base/allocator/partition_allocator/partition_alloc.cc

@@ -193,7 +193,8 @@ void PartitionAllocGlobalInit(OomFunction on_out_of_memory) {
 }
 
 void PartitionAllocGlobalUninitForTesting() {
-#if defined(PA_HAS_64_BITS_POINTERS)
+#if defined(PA_HAS_64_BITS_POINTERS) && \
+    !BUILDFLAG(USE_PARTITION_ALLOC_AS_MALLOC)
   if (IsPartitionAllocGigaCageEnabled())
     internal::PartitionAddressSpace::UninitForTesting();
 #endif