tests: Add test for nested while with exc and break.

tests/basics/while_nest_exc.py

@@ -0,0 +1,13 @@
+# test nested whiles within a try-except
+
+while 1:
+    print(1)
+    try:
+        print(2)
+        while 1:
+            print(3)
+            break
+    except:
+        print(4)
+    print(5)
+    break