[test suite] minor popen_cmd() status update
[test suite] rc file time offset tests
[test suite] basic ops get key tests
[test suite] basic ops save rc stanza time offset tests
[test suite] basic ops save rc stanza time offset minus test
[test suite] basic ops save rc stanza --encryption-mode tests
[test suite] remove .gcno files in --profile-coverage-init mode
[test suite] ensure to recompile for gcov coverage analysis
[test suite] additional save rc file variable coverage