[FrameworkBundle] Added performance tweak to DelegatingLoader

| Q             | A
| ------------- | ---
| Bug fix?      |no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | 
| License       | MIT
| Doc PR        | 

This patch had huge execution time impact on my system because the parsing of the controller names throws an exception if it fails (and it failed a lot in my config). so i added a check before parsing to check if the controller string can be parsed