Introduce intrinsic to expose debug state to generated code.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index f1720f444247d83635c84d00a99cf2457ee0022e..6f3d1ec8bc0ed90b964910d0dbc3b1a143c4e24f 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -6115,6 +6115,11 @@ class HObjectAccess V8_FINAL {
                          Handle<String>::null(), false, false);
   }
 
+  static HObjectAccess ForExternalUInteger8() {
+    return HObjectAccess(kExternalMemory, 0, Representation::UInteger8(),
+                         Handle<String>::null(), false, false);
+  }
+
   // Create an access to an offset in a fixed array header.
   static HObjectAccess ForFixedArrayHeader(int offset);