RFR: 8143142: AssertionError in MethodHandleImpl

[Claes Redestad]

Hi,

it seems I've been testing assertions with the wrong flag.

8142334 added the same assertion check to MethodHandleImpl that was 
there for DirectMethodHandle, which
due to some bootstrapping dependency fails for the MethodHandleImpl 
case. This patch removes that assertion:

webrev: http://cr.openjdk.java.net/~redestad/8143142/webrev.01/
bug: https://bugs.openjdk.java.net/browse/JDK-8143142

/Claes