RFR(S): 8166156: Convert test_semaphore to GTest

[Kirill Zhaldybin]

Dear all,

Could you please review this fix for 8166156?
Pretty straight-forward conversion.

WebRev: http://cr.openjdk.java.net/~kzhaldyb/webrevs/JDK-8166156/webrev.00/
CR: https://bugs.openjdk.java.net/browse/JDK-8166156

Thank you.

Regards, Kirill