Review request for JDK-8007060

[Hannes Wallnoefer]

Please review http://cr.openjdk.java.net/~hannesw/8007060/

This removes the NashornInvocationTarget class whose purpose was to 
track primitiveness of callsite targets and replaces it in two ways.

1) For functions invoked via ScriptRuntime.apply() (this includes 
ordinary megamorphic callsites) we simply check function strictness and 
this-argument primitiveness at runtime. We should have done that anyway, 
I think there were several uses of this method that forgot to wrap 
primitives when they should have.

2) For ordinary monomorphic callsites we check function strictness and 
this-argument primitiveness at link time. If this is primitive we 
install a wrapper methodhandle as argument filter. We then use a new 
NonStrictFunctionGuard that in addition to the FunctionGuard check tests 
whether primitiveness of this-argument has changed by doing one simple 
instanceof check. (This should be very rare, as invocation of script 
functions on JS primitives should generally be rare.

I've tested this with test, test262parallel, and octane. Haven't tested 
node.jar yet. Haven't done any in-depth performance tests but I think 
there should be no notable regression.

thanks,
Hannes