[debug] remove StepFrame

src/debug/debug.h

Index: src/debug/debug.h
diff --git a/src/debug/debug.h b/src/debug/debug.h
index 810f8d2215b0e3daf90db66f4eb514da2325defb..cb031fbd0eda0d683977fdad569dc0906cdbc182 100644
--- a/src/debug/debug.h
+++ b/src/debug/debug.h
@@ -40,9 +40,7 @@ enum StepAction : int8_t {
   StepNext = 1,   // Step to the next statement in the current function.
   StepIn = 2,     // Step into new functions invoked or the next statement
                   // in the current function.
-  StepFrame = 3,  // Step into a new frame or return to previous frame.
-
-  LastStepAction = StepFrame
+  LastStepAction = StepIn
 };
 
 // Type of exception break. NOTE: These values are in macros.py as well.