[rubygems/rubygems] Revert "mustermann depends on URI::RFC2396_PARSER behavior"

This reverts commit https://github.com/rubygems/rubygems/commit/82b25dd75afd.

https://github.com/rubygems/rubygems/commit/16adf53f23

spec/bundler/install/gems/dependency_api_fallback_spec.rb

@@ -12,9 +12,6 @@ RSpec.describe "gemcutter's dependency API" do
 
       require_relative "../../support/artifice/endpoint_timeout"
 
-      # mustermann depends on URI::RFC2396_PARSER behavior
-      URI.parser = URI::RFC2396_PARSER if URI.respond_to?(:parser=)
-
       require "rackup/server"
 
       @t = Thread.new do
@@ -36,8 +33,6 @@ RSpec.describe "gemcutter's dependency API" do
       Artifice.deactivate
       @t.kill
       @t.join
-
-      URI.parser = URI::DEFAULT_PARSER if URI.respond_to?(:parser=)
     end
 
     it "times out and falls back on the modern index" do