Idlelib: forward port changes that silenced 2.7 -3 deprecation warnings and

which are at least as efficient. On Py3, unpacking exceptions never works.

Lib/idlelib/Debugger.py

@@ -254,8 +254,7 @@ class Debugger:
             self.sync_source_line()
 
     def show_frame(self, stackitem):
-        frame, lineno = stackitem
-        self.frame = frame
+        self.frame = stackitem[0]  # lineno is stackitem[1]
         self.show_variables()
 
     localsviewer = None

Lib/idlelib/SearchEngine.py

@@ -83,11 +83,9 @@ class SearchEngine:
         try:
             prog = re.compile(pat, flags)
         except re.error as what:
-            try:
-                msg, col = what
-            except:
-                msg = str(what)
-                col = -1
+            args = what.args
+            msg = args[0]
+            col = arg[1] if len(args) >= 2 else -1
             self.report_error(pat, msg, col)
             return None
         return prog