[Threading][Windows] Link the unit test against Synchronization.lib
[Threading][Windows] Link the unit test against Synchronization.lib

We need to link the threading unit test against Synchronization.lib
to pick up the Win32 APIs we're using.

rdar://90776105

JGiola/swift,roambotics/swift,glessard/swift,roambotics/swift,JGiola/swift,JGiola/swift,JGiola/swift,glessard/swift,glessard/swift,roambotics/swift,glessard/swift,benlangmuir/swift,glessard/swift,benlangmuir/swift,apple/swift,benlangmuir/swift,roambotics/swift,benlangmuir/swift,glessard/swift,JGiola/swift,apple/swift,benlangmuir/swift,apple/swift,apple/swift,roambotics/swift,roambotics/swift,JGiola/swift,apple/swift,apple/swift,benlangmuir/swift