Ensure that promotion queue does not overlap with objects relocated to ToSpace.

src/spaces.h

Index: src/spaces.h
diff --git a/src/spaces.h b/src/spaces.h
index 45e008c00220b9bb4baf5d49d26dc398e43bd7b6..44584ad235abe8f526118504d4450dd4512474cc 100644
--- a/src/spaces.h
+++ b/src/spaces.h
@@ -2140,9 +2140,7 @@ class NewSpace : public Space {
   Address* allocation_top_address() { return &allocation_info_.top; }
   Address* allocation_limit_address() { return &allocation_info_.limit; }
 
-  MUST_USE_RESULT MaybeObject* AllocateRaw(int size_in_bytes) {
-    return AllocateRawInternal(size_in_bytes);
-  }
+  MUST_USE_RESULT INLINE(MaybeObject* AllocateRaw(int size_in_bytes));
 
   // Reset the allocation pointer to the beginning of the active semispace.
   void ResetAllocationInfo();
@@ -2268,8 +2266,7 @@ class NewSpace : public Space {
   HistogramInfo* allocated_histogram_;
   HistogramInfo* promoted_histogram_;
 
-  // Implementation of AllocateRaw.
-  MUST_USE_RESULT inline MaybeObject* AllocateRawInternal(int size_in_bytes);
+  MUST_USE_RESULT MaybeObject* SlowAllocateRaw(int size_in_bytes);
 
   friend class SemiSpaceIterator;