Add basic try-finally testcase.

It's mildly suprising these work without further changes to exception
handling code (the only change required was to handle SETUP_FINALLY).

tests/basics/try-finally1.py

+print("noexc-finally")
+try:
+    print("try")
+finally:
+    print("finally")
+
+print("noexc-finally-finally")
+try:
+    print("try1")
+    try:
+        print("try2")
+    finally:
+        print("finally2")
+finally:
+    print("finally1")
+print()
+
+print("noexc-finally-func-finally")
+def func2():
+    try:
+        print("try2")
+    finally:
+        print("finally2")
+
+try:
+    print("try1")
+    func2()
+finally:
+    print("finally1")
+print()
+
+
+print("exc-finally-except")
+try:
+    print("try1")
+    try:
+        print("try2")
+        foo()
+    except:
+        print("except2")
+finally:
+    print("finally1")
+print()
+
+print("exc-finally-except-filter")
+try:
+    print("try1")
+    try:
+        print("try2")
+        foo()
+    except NameError:
+        print("except2")
+finally:
+    print("finally1")
+print()
+
+
+print("exc-except-finally-finally")
+try:  # top-level catch-all except to not fail script
+    try:
+        print("try1")
+        try:
+            print("try2")
+            foo()
+        finally:
+            print("finally2")
+    finally:
+        print("finally1")
+except:
+    print("catch-all except")
+print()