Introduce bytecodes for assisting generator suspend and resume.

src/compiler/code-assembler.h

Index: src/compiler/code-assembler.h
diff --git a/src/compiler/code-assembler.h b/src/compiler/code-assembler.h
index f7333bb59d682fec304503a8a447355fb8bf20af..2f46d0a878408ef2233674f35564ab6b84c42c24 100644
--- a/src/compiler/code-assembler.h
+++ b/src/compiler/code-assembler.h
@@ -244,6 +244,8 @@ class CodeAssembler {
   Node* TruncateFloat64ToInt32JavaScript(Node* a);
   // No-op on 32-bit, otherwise zero extend.
   Node* ChangeUint32ToWord(Node* value);
+  // No-op on 32-bit, otherwise sign extend.
+  Node* ChangeInt32ToIntPtr(Node* value);
 
   // Projections
   Node* Projection(int index, Node* value);