[turbofan] Introduce integer multiplication with overflow.

src/compiler/arm64/instruction-codes-arm64.h

Index: src/compiler/arm64/instruction-codes-arm64.h
diff --git a/src/compiler/arm64/instruction-codes-arm64.h b/src/compiler/arm64/instruction-codes-arm64.h
index 2b5fe331bc8546bca10292bd8d2ae717d5e8b9bd..b10864257830bab6a67097f8343c29353e4c3596 100644
--- a/src/compiler/arm64/instruction-codes-arm64.h
+++ b/src/compiler/arm64/instruction-codes-arm64.h
@@ -177,7 +177,8 @@ namespace compiler {
   V(Operand2_R_UXTB)  /* %r0 UXTB (unsigned extend byte) */     \
   V(Operand2_R_UXTH)  /* %r0 UXTH (unsigned extend halfword) */ \
   V(Operand2_R_SXTB)  /* %r0 SXTB (signed extend byte) */       \
-  V(Operand2_R_SXTH)  /* %r0 SXTH (signed extend halfword) */
+  V(Operand2_R_SXTH)  /* %r0 SXTH (signed extend halfword) */   \
+  V(Operand2_R_SXTW)  /* %r0 SXTW (signed extend word) */
 
 enum ResetJSSPAfterCall { kNoResetJSSP, kResetJSSP };