docker_run_tests.sh: stop using cmake

Use test_driver directly instead of CMake in the docker tests.

Deal with the read-only "/fish-source" by exporting
"CARGO_TARGET_DIR=$HOME/fish-build".  It seems correct to also inject this
environment variable into the interactive debugging shells.  Add some logging
to make this override more obvious to the user.

Adopt "build_tools/check.sh", because that defines the full set of checks
that we (eventually) want to run in CI.

In particular, this will also run "tests/checks/po-files-up-to-date.fish"
which "cargo b && cargo t && tests/test_driver.py" does not, due to the
REQUIRES clause.

Since most docker images have some lints/warnings today, disable those for
now. Use "docker_run_tests.sh --lint" to override. The default may be changed
in future.

docker/context/fish_run_tests.sh

@@ -5,24 +5,32 @@ set -e
 # This script is copied into the root directory of our Docker tests.
 # It is the entry point for running Docker-based tests.
 
-cd ~/fish-build
+cd /fish-source
 git config --global --add safe.directory /fish-source
-cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug /fish-source "$@"
+
+export CARGO_TARGET_DIR="$HOME"/fish-build
+
+interactive_shell() {
+    echo
+    echo "+ export=CARGO_TARGET_DIR=$CARGO_TARGET_DIR"
+    echo
+    bash -i
+}
 
 # Spawn a shell if FISH_RUN_SHELL_BEFORE_TESTS is set.
 if test -n "$FISH_RUN_SHELL_BEFORE_TESTS"
 then
-    bash -i
+    interactive_shell
 fi
 
 set +e
-ninja && ninja fish_run_tests
+build_tools/check.sh
 RES=$?
 set -e
 
 # Drop the user into a shell if FISH_RUN_SHELL_AFTER_TESTS is set.
 if test -n "$FISH_RUN_SHELL_AFTER_TESTS"; then
-    bash -i
+    interactive_shell
 fi
 
 exit $RES