Suppress warnings in make test-all

suppress "warning: Pattern matching is experimental, and the behavior may change in future versions of Ruby!"

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@67595 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

test/ruby/test_pattern_matching.rb

@@ -1,6 +1,10 @@
 # frozen_string_literal: true
 require 'test/unit'
 
+verbose, $VERBOSE = $VERBOSE, nil # suppress "warning: Pattern matching is experimental, and the behavior may change in future versions of Ruby!"
+eval "#{<<~"begin;"}\n#{<<~'end;'}".gsub(/^.*# fix indent\n/, ''), binding, __FILE__, __LINE__+2
+begin;
+end # fix indent
 class TestPatternMatching < Test::Unit::TestCase
   class C
     class << self
@@ -1085,3 +1089,6 @@ END
     end
   end
 end
+begin # fix indent
+end;
+$VERBOSE = verbose