Fix parameter adjustment with dictionary

Fix parameter adjustment with dictionary

The new advanced API basically set `requestedParams = appliedParams` when
using a dictionary. This halted all parameter adjustment, which can hurt
compression ratio if, for example, the window log is small for the first
call, but the rest of the files are large.

This patch fixes the bug, and checks that the `requestedParams` don't change
in the new advanced API when using a dictionary, and generally in the fuzzer.