Add current benchmarks, new benchmark List[T].indexOfOpt with variants

testcases/synthesis/archives/Unification.scala

testcases/synthesis/archives/ZuneBug.scala

testcases/synthesis/current/AddressBook/Make.scala

testcases/synthesis/current/AddressBook/Merge.scala

testcases/synthesis/current/BatchedQueue/Dequeue.scala

testcases/synthesis/current/BatchedQueue/Enqueue.scala

testcases/synthesis/current/Compiler/Desugar.scala

testcases/synthesis/current/Compiler/DesugarImplies.scala

testcases/synthesis/current/Compiler/RewriteImplies.scala

testcases/synthesis/current/Compiler/RewriteMinus.scala

testcases/synthesis/current/List/Delete.scala

testcases/synthesis/current/List/Diff.scala

testcases/synthesis/current/List/IndexOfInt.scala

testcases/synthesis/current/List/IndexOfOpt.scala

testcases/synthesis/current/List/IndexOfOpt2.scala

testcases/synthesis/current/List/Insert.scala

testcases/synthesis/current/List/Split.scala

testcases/synthesis/current/List/Union.scala

testcases/synthesis/current/Parentheses/Par.scala

testcases/synthesis/current/SortedList/Delete.scala