On some platforms like qemu/x86_64/sel4, accessing the file system is so
slow that it used to hit the timeout of this phase in the run script.
Ref #5148
The script tests the use of an encrypted file system that is created and
provided via the File Vault.
Furthermore the script can be used for test-driving existing File-Vault
containers (created with potentially older File-Vault versions) under the
current File-Vault version. This is done via the "LX_FS_DIR_TEMPLATE"
env variable.
Ref #5062
