resourceloader: Shorten cache expiry if 'version' query doesn't match

resourceloader: Shorten cache expiry if 'version' query doesn't match

Versioned load.php requests (load.php?modules=..&version=..) are highly
cacheable due to being versioned. When a module changes, the startup module
delivers new metadata to the client which naturally results in a cache miss
by producing a different url.

However, during upgrades and other deployments it was possible for a
multi-server installation to pollute edge caches with outdated content
in the following scenario:

* Deployment starts for an upgrade from version A to version B.
* Server 1 (on version B) gets a request for the startup manifest.
  Client receives new manifest with version B information
  and makes a versioned request for version B.
* Server 2 (still on version A) responds to this request with the
  version it has (which is version A).
* Edge cache will store version A under the new url for version B.

This commit changes the last point by setting a low max-age when a request
has a 'version' hash mismatch.

Test plan:
* Look for a request in your browser like:
 '/load.php?..modules=jquery%2Cmediawiki..&version=..'
* Verify it has a high Cache-Control max-age.
* Manipulate the 'version' parameter and verify it gets a low max-age.

Bug: T117587
Change-Id: Iba89c09b7b71d9fd2a8ff3ebe2618e26ea9daddf