PartitionAllocator destructor should not have a return value.

This breaks GCC (but it should break any platform, a destructor
specification should never have a return value.

Bug: 819294
Change-Id: I2741ce5c10526a8e11914882449d0b207e755201
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2304573Reviewed-by: Benoit L <lizeb@chromium.org>
Commit-Queue: José Dapena Paz <jdapena@igalia.com>
Cr-Commit-Position: refs/heads/master@{#789470}

base/allocator/partition_allocator/partition_alloc.cc

@@ -831,11 +831,10 @@ void PartitionAllocator<thread_safe>::init(
       &partition_root_);
 }
 
-template void PartitionAllocator<internal::ThreadSafe>::~PartitionAllocator();
+template PartitionAllocator<internal::ThreadSafe>::~PartitionAllocator();
 template void PartitionAllocator<internal::ThreadSafe>::init(
     PartitionAllocatorAlignment alignment);
-template void
-    PartitionAllocator<internal::NotThreadSafe>::~PartitionAllocator();
+template PartitionAllocator<internal::NotThreadSafe>::~PartitionAllocator();
 template void PartitionAllocator<internal::NotThreadSafe>::init(
     PartitionAllocatorAlignment alignment);