tree-wide: Update outdated docs on removed old integration test stuff

docs/CODE_QUALITY.md

@@ -21,9 +21,10 @@ available functionality:
    change these flags for an already set up build tree, too, with "meson
    configure -C build -D…".)
 
-2. Use `./test/run-integration-tests.sh` to run the full integration test
-   suite. This will build OS images with a number of integration tests and run
-   them using `systemd-nspawn` and `qemu`. Requires root.
+2. Run the full integration test suite as described in
+   [test/README.md](/../test/README.md). This will build OS images with a number
+   of integration tests and run them using `systemd-nspawn` and `qemu`. Requires
+   root.
 
 3. Use `./coccinelle/run-coccinelle.sh` to run all
    [Coccinelle](http://coccinelle.lip6.fr/) semantic patch scripts we ship. The

docs/TESTING_WITH_SANITIZERS.md

@@ -102,5 +102,4 @@ make things work as expected in most cases. This will, obviously, not work with
 statically linked sanitizer libraries.
 
 These shenanigans are performed automatically when running the integration test
-suite (i.e. `test/TEST-??-*`) and are located in `test/test-functions` (mainly,
-but not only, in the `create_asan_wrapper` function).
+suite.