enable Dispatch tests in TestNSOperationQueue

[dgrove-oss]

After you merge #551 and Dispatch is enabled by default, both of these tests will now pass and can be enabled.

[parkera]

Alright, so dispatch should be enabled now. Let's try it out by testing this PR.

[parkera]

@swift-ci please test linux

[parkera]

Good news - it built! Bad news - it failed.

Test Suite 'TestNSOperationQueue' started at 06:08:24.096
Test Case 'TestNSOperationQueue.test_OperationPriorities' started at 06:08:24.096
fatal error: Index out of range: file /home/buildnode/disk2/workspace/swift-corelibs-foundation-PR-Linux/swift/stdlib/public/core/ContiguousArrayBuffer.swift, line 366
Current stack trace:
0    libswiftCore.so                    0x00007f23921ca250 swift_reportError + 117

[seabaylea]

@parkera Looks like the CI ran whilst it still wasn't configured to build libdispatch - the build configuration written to the log contains:

--skip-build-libdispatch

Testing locally with the latest master, this works for me. Could you try re-running the CI test?

[parkera]

@swift-ci please test linux

[parkera]

Sure thing

[parkera]

Passed!