tests: prepare for introduction of -e inject= option

tests: prepare for introduction of -e inject= option

Rename files related to fault injection to avoid further confusion.

* tests/fault_injection-exit_group.expected: Rename
to tests/qual_fault-exit_group.expected.
* tests/fault_injection-exit_group.test: Rename
to tests/qual_fault-exit_group.test.
* tests/fault_syntax.test: Rename to tests/qual_fault-syntax.test.
* tests/fault_injection.c: Rename to tests/qual_fault.c.
* tests/fault_injection.test: Rename to tests/qual_fault.test.
* tests/fault_injection-retval.c: Rename to tests/qual_inject-retval.c.
* tests/fault_injection-retval.test: Rename
to tests/qual_inject-retval.test.
* tests/fault_injection.sh: Rename to tests/scno_tampering.sh.
* tests/.gitignore: Update.
* tests/Makefile.am (check_PROGRAMS, DECODER_TESTS, MISC_TESTS,
EXTRA_DIST): Update.