Removed StressTest.LinkAndUnlinkFileNameManyTimesInParallel.
Removed StressTest.LinkAndUnlinkFileNameManyTimesInParallel.

This fails regularly with EIO due to both open(2) and write(2) causing
a read of the file contents, which fails because the underlying object
has already been removed.

GoogleCloudPlatform/gcsfuse,kahing/gcsfuse,BanzaiMan/gcsfuse,mbrukman/gcsfuse,jacobsa/timeutil,GoogleCloudPlatform/gcsfuse,jacobsa/ratelimit,GoogleCloudPlatform/gcsfuse,BanzaiMan/gcsfuse