Test that Truffle options are correctly applied

(cherry picked from commit 95628b6836aad1b371bee733044af74d77906c14)

Author: eregon

spec/truffle/launcher_spec.rb

@@ -280,4 +280,15 @@ def should_print_full_java_command(options, env: {})
     out.should include(':b')
   end
 
+  guard -> { TruffleRuby.graal? } do
+    it "applies Truffle options" do
+      prefix = TruffleRuby.native? ? '--native.' : '--jvm.'
+      options = [
+        "#{prefix}Dgraal.TraceTruffleCompilation=true",
+        "#{prefix}Dgraal.TruffleBackgroundCompilation=false",
+      ].join(" ")
+      out = ruby_exe("2000.times {}", options: options)
+      out.should include("[truffle] opt done")
+    end
+  end
 end