Remove PolySameLen

[panacekcz]

The @PolySameLen annotation is redundant and can be replaced by @SameLen annotations.
For example, a method

Object @PolySameLen[] m(Object @PolySameLen[] a){
 return a;
}

can be annotated

Object @SameLen("#1")[] m(Object[] a){
 return a;
}

The latter expresses the same property as the former, and seems to work better.

The annotation @PolyLength can be replaced by @PolyValue @SameLen.
For example, @PolyLength String intern(@PolyLength String this) can be changed to @PolyValue @SameLen("this") String intern(@PolyValue String this).