Port bundle exec warning check to RSpec example

Merged: https://github.com/ruby/ruby/pull/12096

spec/bundler/bundled_gems_spec.rb

@@ -62,6 +62,18 @@ RSpec.describe "bundled_gems.rb" do
     expect(err).to include("You can add net-smtp")
   end
 
+  it "Show warning when bundle exec with ruby and script" do
+    code = <<-RUBY
+      require "ostruct"
+    RUBY
+    create_file("script.rb", code)
+    create_file("Gemfile", "source 'https://rubygems.org'")
+
+    bundle "exec ruby script.rb"
+
+    expect(err).to include(/ostruct was loaded from (.*) from Ruby 3.5.0/)
+  end
+
   it "Show warning when warn is not the standard one in the current scope" do
     script <<-RUBY
       module My

tool/test_for_warn_bundled_gems/test.sh

@@ -4,10 +4,6 @@ echo "* Show warning sub-feature like bigdecimal/util"
 ruby test_warn_sub_feature.rb
 echo
 
-echo "* Show warning when bundle exec with ruby and script"
-bundle exec ruby test_warn_bundle_exec.rb
-echo
-
 echo "* Show warning when bundle exec with shebang's script"
 bundle exec ./test_warn_bundle_exec_shebang.rb
 echo

tool/test_for_warn_bundled_gems/test_warn_bundle_exec.rb

@@ -1 +0,0 @@
-require "base64"