Reland of "[heap] Parallel newspace evacuation, semispace copy, and compaction \o/"

src/globals.h

Index: src/globals.h
diff --git a/src/globals.h b/src/globals.h
index 0e24d5933269ca0f00cb212e03173dba50da1c45..e78844cf20c00bb7177dcbef38f15baa64908030 100644
--- a/src/globals.h
+++ b/src/globals.h
@@ -1058,6 +1058,14 @@ inline FunctionKind WithObjectLiteralBit(FunctionKind kind) {
   DCHECK(IsValidFunctionKind(kind));
   return kind;
 }
+
+inline uint32_t ObjectHash(Address address) {
+  // All objects are at least pointer aligned, so we can remove the trailing
+  // zeros.
+  return static_cast<uint32_t>(bit_cast<uintptr_t>(address) >>
+                               kPointerSizeLog2);
+}
+
 }  // namespace internal
 }  // namespace v8