Dead code in WebTestBase

This was found in #2584603: PHP exception on manage fields after enabling Configuration Translation

Problem/Motivation

In WebTestBase::setUp() $this->installParameters() is called and the parameters are then passed into $this->doInstall(). That method does document a $parameters variable but it never actually uses it but instead calls $this->installParameters() itself.

Proposed resolution

Remove the unneeded argument and superfluous method call.

This is 100% backwards compatible and only changes test code so is eligible during the RC.

Remaining tasks

User interface changes

None.

API changes

None.

Data model changes

None.