[9] RFR of 8133010: (fs) Create test for parallel access to Files.probeContentType()

[Brian Burkhalter]

Please review at your convenience.

Issue:	https://bugs.openjdk.java.net/browse/JDK-8133010
Patch:	http://cr.openjdk.java.net/~bpb/8133010/webrev.00/

Summary:

Add as a formal regression test the test submitted with https://bugs.openjdk.java.net/browse/JDK-8080115 in hopes of reproducing the issue which has as yet not occurred when run manually.

Thanks,

Brian