CI: use build_tools/check.sh in Cirrus CI

08b03a733a removed CMake from the Docker images used for the
Cirrus builds.

It might be better to use fish_run_tests.sh in the Docker image, but
that requires some context which I'm not sure is set up properly in
Cirrus.

.cirrus.yml

@@ -25,10 +25,7 @@ linux_task:
         # Unrestriced parallelism results in OOM
         - lscpu || true
         - (cat /proc/meminfo | grep MemTotal) || true
-        - mkdir build && cd build
-        - FISH_TEST_MAX_CONCURRENCY=6 cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug ..
-        - ninja -j 6 fish
-        - ninja fish_run_tests
+        - FISH_TEST_MAX_CONCURRENCY=6 build_tools/check.sh
     only_if: $CIRRUS_REPO_OWNER == 'fish-shell'
 
 linux_arm_task:
@@ -44,11 +41,7 @@ linux_arm_task:
         # Unrestriced parallelism results in OOM
         - lscpu || true
         - (cat /proc/meminfo | grep MemTotal) || true
-        - mkdir build && cd build
-        - FISH_TEST_MAX_CONCURRENCY=6 cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug ..
-        - ninja -j 6 fish
-        - file ./fish
-        - ninja fish_run_tests
+        - FISH_TEST_MAX_CONCURRENCY=6 build_tools/check.sh
     # CI task disabled during RIIR transition
     only_if: false && $CIRRUS_REPO_OWNER == 'fish-shell'
 
@@ -68,10 +61,7 @@ freebsd_task:
         - pw user add -n fish-user -s /bin/csh -d /home/fish-user
         - mkdir -p /home/fish-user
         - chown -R fish-user /home/fish-user
-        - mkdir build && cd build
-        - chown -R fish-user ..
+        - chown -R fish-user .
         - sudo -u fish-user -s whoami
-        - sudo -u fish-user -s FISH_TEST_MAX_CONCURRENCY=1 cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug ..
-        - sudo -u fish-user -s ninja -j 6 fish
-        - sudo -u fish-user -s ninja fish_run_tests
+        - sudo -u fish-user -s FISH_TEST_MAX_CONCURRENCY=1 build_tools/check.sh
     only_if: $CIRRUS_REPO_OWNER == 'fish-shell'