Combine DEBUG_BREAK and DEBUG_PREPARE_STEP_IN into one IC stub kind DEBUG_STUB, encoding DEBUG_BREA…

src/debug.h

Index: src/debug.h
diff --git a/src/debug.h b/src/debug.h
index 150e29e3089afaa642add18f4176e49c27e4bc45..2fb949f7e26d153fabe15d686720d687fb7ec16b 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -79,6 +79,12 @@ enum BreakLocatorType {
 };
 
 
+enum DebugExtraICState {
+  DEBUG_BREAK,
+  DEBUG_PREPARE_STEP_IN
+};
+
+
 // Class for iterating through the break points in a function and changing
 // them.
 class BreakLocationIterator {