mtest: move test_count and name_max_len to TestHarness class
mtest: move test_count and name_max_len to TestHarness class

Avoid passing them around as parameters; this will be useful when logging
is moved out of TestHarness, because individual loggers will call back
into TestHarness to do common formatting chores.

Signed-off-by: Paolo Bonzini <69d3ebcf5ee4e7f05a50dc23cd96655b730804b4@redhat.com>

jpakkane/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,jpakkane/meson,pexip/meson,jpakkane/meson,mesonbuild/meson,pexip/meson,jpakkane/meson,jpakkane/meson,QuLogic/meson,pexip/meson,QuLogic/meson,QuLogic/meson,jpakkane/meson,QuLogic/meson,mesonbuild/meson,pexip/meson,jpakkane/meson,QuLogic/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,QuLogic/meson,pexip/meson,pexip/meson,jpakkane/meson,pexip/meson,QuLogic/meson,jpakkane/meson,mesonbuild/meson,QuLogic/meson,QuLogic/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson