Fix wrongPC call

The codegen calls Fiber.wrongPC using INVOKESTATIC
but the implementation is non-static.  To make 
matters simple we just declare the wrongPC
function static.
Fix usage of Detector.commonSuperClass

The code was a bit messy, sometimes passing
"Lfoo/Bar;" and sometimes "foo/Bar".  This
cleans up matters to always use the latter.
Make sure to always call mv.visitEnd()

The MethodWeaver is not following protocol; it
needs to call mv.visitEnd() even for abstract
methods.