java/interp: Fix JVM frame size

If a method is abstract and has no code section, maximum number of local
variables is undefined. Delay local variable frame allocation until we
have resolved the method that is invoked.

Spotted by valgrind.

Signed-off-by: Pekka Enberg <penberg@iki.fi>
java/interp: op_invokeinterface

This is not really the real thing but the lookup procedure is good
enough for now...

Signed-off-by: Pekka Enberg <penberg@iki.fi>