Disable all networks during cache test.

We've seen random apps try downloading things while this test is
running, which causes disk space to fluxuate.

Bug: 63004065
Test: cts-tradefed run commandAndExit cts-dev --abi armeabi-v7a -m CtsAppSecurityHostTestCases -t android.appsecurity.cts.StorageHostTest#testCache
Change-Id: I0203490153af5ebddb06a928727ec42e5ab85cf6
1 file changed