Fix very strange bug in FindBreakLocationFromAddress algorithm

src/runtime.cc

Index: src/runtime.cc
diff --git a/src/runtime.cc b/src/runtime.cc
index 62d044e828dfedf1723ac6e12e581771014d3a42..ff55fab8c95f51359464eb2e80f05ab24c63b792 100644
--- a/src/runtime.cc
+++ b/src/runtime.cc
@@ -11229,7 +11229,9 @@ class ScopeIterator {
     // Find the break point where execution has stopped.
     BreakLocationIterator break_location_iterator(debug_info,
                                                   ALL_BREAK_LOCATIONS);
-    break_location_iterator.FindBreakLocationFromAddress(frame->pc());
+    // pc points to the instruction after the current one, possibly a break
+    // location as well. So the "- 1" to exclude it from the search.
+    break_location_iterator.FindBreakLocationFromAddress(frame->pc() - 1);
     if (break_location_iterator.IsExit()) {
       // We are within the return sequence. At the momemt it is not possible to
       // get a source position which is consistent with the current scope chain.