[FrameworkBundle] fixes cahe:clear command's warmup

Solution taken is to replace the last char of the cache directory name to create a temporary cache directory, this way the temporary cache path has the same length than the real one. I tested this on several projects, in dev and prod environments.

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #6203