Use GetAbsoluteTestTmpdir() rather than hard-code "/tmp"
Use GetAbsoluteTestTmpdir() rather than hard-code "/tmp"

This change makes these tests easier to run on systems that have their temp
directory in another location.

PiperOrigin-RevId: 423904175

google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor,google/gvisor