Replace sleep with polling in AuthFsHostTest

The FUSE mount isn't ready immediately, so there was a sleep to give it
extra time to be ready. This change replaces the sleep by polling the
filesystem type of FUSE. The polling saves 1 second-ish per test case.

Also fix some setup/teardown problem of an output file.

Bug: 178874539
Test: atest

Change-Id: I8d5b728883a06ada4d903251f63e44d51132643f
1 file changed
tree: 0072e26f312922185333f01aad42897d878dc512
  1. apex/
  2. authfs/
  3. docs/
  4. microdroid/
  5. tests/
  6. virtmanager/
  7. vm/
  8. .clang-format
  9. PREUPLOAD.cfg