tests: add expectedFailureIfTemplate decorator
tests: add expectedFailureIfTemplate decorator

Some tests are expected to fail only on some templates (some feature not
available in older distribution, some feature not yet ported to
another).

QubesOS/qubes-core-admin,woju/qubes-core-admin,woju/qubes-core-admin,QubesOS/qubes-core-admin,marmarek/qubes-core-admin,woju/qubes-core-admin,marmarek/qubes-core-admin,QubesOS/qubes-core-admin,woju/qubes-core-admin,marmarek/qubes-core-admin