build: make check-block a meson test

"meson test" can be asked to run tests verbosely; this makes it usable
also for qemu-iotests's own harness, and it lets "make check-block"
reuse mtest2make.py's infrastructure to find and build test dependencies.

Adjust check-block.sh to use the standard exit code that reports a test
as skipped.  Alternatively, in the future we could make it produce TAP
output, which is consistent with all other "make check" tests.

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

tests/qemu-iotests/meson.build

@@ -0,0 +1,29 @@
+if have_tools and targetos != 'windows'
+  qemu_iotests_binaries = [qemu_img, qemu_io, qemu_nbd, qsd]
+  qemu_iotests_env = {'PYTHON': python.full_path()}
+  qemu_iotests_formats = {
+    'qcow2': 'quick',
+    'raw': 'slow',
+    'qed': 'thorough',
+    'vmdk': 'thorough',
+    'vpc': 'thorough'
+  }
+
+  foreach k, v : emulators
+    if k.startswith('qemu-system-')
+      qemu_iotests_binaries += v
+    endif
+  endforeach
+  foreach format, speed: qemu_iotests_formats
+    if speed == 'quick'
+      suites = 'block'
+    else
+      suites = ['block-' + speed, speed]
+    endif
+    test('qemu-iotests ' + format, sh, args: [files('../check-block.sh'), format],
+         depends: qemu_iotests_binaries, env: qemu_iotests_env,
+         suite: suites,
+         timeout: 0,
+         is_parallel: false)
+  endforeach
+endif