Fix filesystem race issue in SampleProfTest introduced in rL342283.
Fix filesystem race issue in SampleProfTest introduced in rL342283.

Before this fix, multiple invocations of testRoundTrip will create multiple
writers which share the same file as output destination. That could introduce
filesystem race issue when multiple subtests are executed concurrently. This
patch assign writers with different files as their output destinations.



git-svn-id: 0ff597fd157e6f4fc38580e8d64ab130330d2411@342301 91177308-0d34-0410-b5e6-96231b3b80d8

llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,llvm-mirror/llvm,llvm-mirror/llvm,llvm-mirror/llvm,apple/swift-llvm,apple/swift-llvm,llvm-mirror/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,GPUOpen-Drivers/llvm,apple/swift-llvm,llvm-mirror/llvm,apple/swift-llvm,GPUOpen-Drivers/llvm,llvm-mirror/llvm