Removed unusefull workaround

Given that Logstash already ships with JRuby 9.4.6.0 which contains the fix jruby/jruby#8061, the workaround to avoid the original bad param numbers can be removed.

lib/bootstrap/rspec.rb

@@ -15,12 +15,6 @@
 # specific language governing permissions and limitations
 # under the License.
 
-# The following line is a workaround needed because starting from JDK 21 LinkedHashSet
-# has a package private map method that JRuby bound as a usable method.
-# It's mainly related to Gradle opening java.base module and this interfere with
-# JRuby binding of methods. Full description at https://github.com/jruby/jruby/issues/8061#issuecomment-1908807511
-# Remove when Logstash bundle a JRuby version >= 9.4.6.0.
-# java.util.LinkedHashSet.remove_method(:map) rescue nil
 
 require_relative "environment"
 LogStash::Bundler.setup!({:without => [:build]})