[ftr] Speed up FTR code owner check (#205093)

## Summary

Switch to one matcher w/ all code owner patterns rather than separate
matchers for each code owner pattern. Reduces the run time of
`scripts/check_ftr_code_owners.js` by ~10x.

### Before
```console
▶ node scripts/check_ftr_code_owners.js
 info Reading CODEOWNERS file
 info Checking ownership for 8653 test files (this will take a while)
 info Ownership check complete (took 18.89 s)
 succ All test files have a code owner. 🥳
```

#### After
```console
▶ node scripts/check_ftr_code_owners.js
 info Checked 8653 test files in 1.59s
 succ All test files have a code owner 🥳
```

scripts/check_ftr_code_owners.js

@@ -8,4 +8,4 @@
  */
 
 require('../src/setup_node_env');
-require('@kbn/test').runCheckFtrCodeOwnersCli();
+void require('@kbn/test').checkFTRCodeOwnersCLI();