Add failing codegen test (reduced from subprocess.py)

We currently can't deopt from inside an exception block.

test/tests/regr_test.py

+import types
+def f(self, args):
+    if isinstance(args, types.StringTypes):
+        pass
+
+
+    try:
+        self.pid
+    except:
+        pass
+
+
+class C(object):
+    pass
+c = C()
+c.pid = 1
+for i in xrange(20000):
+    f(c, None)