Backported JDK8 Indy things that allow us to turn a DynamicMethodSymbol into an Indy call
Attr: turn a JCIndyIdent into a DynamicMethodSymbol
FIXUP JDK8 backport
Added JCTree.JCIndyIdent to make Indy calls #1102
CallBuilder: added prependArgument to be able to prepend instance arguments for Indy calls