Make all_backends' test_suite manual
Make all_backends' test_suite manual

A test_suite itself does not get run when enumerating :all in a
package. If a test_suite is not tagged "manual", all of its tests
are added to the enumeration, even if all those tests are individually
tagged "manual".

PiperOrigin-RevId: 281196824
Change-Id: I37170ee4ea8943bab021fa9ac272db15a590ebb4

google/asylo,google/asylo,google/asylo,google/asylo,google/asylo,google/asylo