changed local extensions priority

local extensions aren't longer chosen before members
KT-3563 Compiler requiring java.io.File, and it's unclear why
 #KT-3563 fixed
refactoring
  extracted methods
report UNRESOLVED_REFERENCE_WRONG_RECEIVER
 mentioning candidates with wrong receiver
added ThrowingScope
fixed npe in comparing results
refactoring
 extracted checkReceiverTypeError method to avoid 'checkOnlyReceiverTypeError' boolean flag