Remove unused code from java.lang.invoke

While working with java.lang.invoke startup improvements in JDK-8142334, a few protected methods that are never used were identified and should be removed, including:

 LambdaForm.addArguments
 LambdaForm.permuteArguments
 LambdaForm.permutedTypesMatched

Several of these seem to have been left behind when LambdaFormEditor was introduced.