Increase regexp timeout and allow override (#32056)

config/initializers/regexp.rb

@@ -1,4 +1,4 @@
 # frozen_string_literal: true
 
-# 0.5s is a fairly high timeout, but that should account for slow servers under load
-Regexp.timeout = 0.5 if Regexp.respond_to?(:timeout=)
+# 2s is a fairly high default, but that should account for slow servers under load
+Regexp.timeout = ENV.fetch('REGEXP_TIMEOUT', 2).to_f if Regexp.respond_to?(:timeout=)