added content length header to BinaryFileResponse
bug #9412 [HttpFoundation] added content length header to BinaryFileResponse (kbond)

This PR was submitted for the master branch but it was merged into the 2.2 branch instead (closes #9412).

Discussion
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[HttpFoundation] added content length header to BinaryFileResponse

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #9256, #7684
| License       | MIT
| Doc PR        | n/a

Commits
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e75a556 added content length header to BinaryFileResponse