4741726: allow Object += String
Summary: remove code in line with restriction removed from JLS
Reviewed-by: mcimadamore
Contributed-by: michaelbailey0@gmail.com
1 T6230128.java:11:10: compiler.err.override.weaker.access: (- compiler.misc.cant.override: foo(java.lang.Object...), A1a, foo(java.lang.Object[]), A1), public