[heap] remove unused PageSpace::AllocateRawUnalignedSynchronized

R=mlippautz@chromium.org

Bug: 
Change-Id: I0df355cdfcf77a1462948b82479f2626d94ca5cc
Reviewed-on: https://chromium-review.googlesource.com/614623Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Ali Ijaz Sheikh <ofrobots@google.com>
Cr-Commit-Position: refs/heads/master@{#47381}

src/heap/spaces-inl.h

@@ -358,13 +358,6 @@ AllocationResult PagedSpace::AllocateRawUnaligned(
 }
 
 
-AllocationResult PagedSpace::AllocateRawUnalignedSynchronized(
-    int size_in_bytes) {
-  base::LockGuard<base::Mutex> lock_guard(&space_mutex_);
-  return AllocateRawUnaligned(size_in_bytes);
-}
-
-
 // Raw allocation.
 AllocationResult PagedSpace::AllocateRawAligned(int size_in_bytes,
                                                 AllocationAlignment alignment) {

src/heap/spaces.h

@@ -2046,9 +2046,6 @@ class V8_EXPORT_PRIVATE PagedSpace : NON_EXPORTED_BASE(public Space) {
   MUST_USE_RESULT inline AllocationResult AllocateRawUnaligned(
       int size_in_bytes, UpdateSkipList update_skip_list = UPDATE_SKIP_LIST);
 
-  MUST_USE_RESULT inline AllocationResult AllocateRawUnalignedSynchronized(
-      int size_in_bytes);
-
   // Allocate the requested number of bytes in the space double aligned if
   // possible, return a failure object if not.
   MUST_USE_RESULT inline AllocationResult AllocateRawAligned(