search: remove dead FuzzifyRegexpPatterns

Created by: rvantonder

This is dead. It was for globbing introduced in https://github.com/sourcegraph/sourcegraph/pull/12659 but since we've changed our suggestions code it doesn't apply any more. There still exists some globbing logic I want to keep since I have an experimental branch to support this, but we won't need the suggestion logic.

Test plan

Removes dead code.