tests/basics: Add test case for overflowing Py stack in try-finally.

tests/basics/try_finally2.py

+# check that the Python stack does not overflow when the finally
+# block itself uses more stack than the rest of the function
+def f1(a, b):
+    pass
+def test1():
+    val = 1
+    try:
+        raise ValueError()
+    finally:
+        f1(2, 2) # use some stack
+        print(val) # check that the local variable is the same
+try:
+    test1()
+except ValueError:
+    pass
+
+# same as above but with 3 args instead of 2, to use an extra stack entry
+def f2(a, b, c):
+    pass
+def test2():
+    val = 1
+    try:
+        raise ValueError()
+    finally:
+        f2(2, 2, 2) # use some stack
+        print(val) # check that the local variable is the same
+try:
+    test2()
+except ValueError:
+    pass