[SPARK-4169] [Core] Accommodate non-English Locales in unit tests

For me the core tests failed because there are two locale dependent parts in the code.
Look at the Jira ticket for details.

Why is it necessary to check the exception message in isBindCollision in
https://github.com/apache/spark/blob/master/core/src/main/scala/org/apache/spark/util/Utils.scala#L1686
?
There's probably not a whole lot of harm in a false-positive here, since I think we limit the number of retries and will eventually fail.