Change error message in MutableDataStructures

Why would we use use `java.util` instead?
Change error message in MutableDataStructuresTest accordingly
Added wart for DefaultArguments
Remove synthetics from default param check
Renamed test
Merge pull request #83 from maxpow4h/doom-arguments

Added wart for DefaultArguments
Merge pull request #82 from michalrus/mutable-ds-error-msg

Change error message in MutableDataStructures