[PRISM] Enable RubyVM tests for prism

test/.excludes-prism/TestRubyVM.rb

@@ -1 +0,0 @@
-exclude(:test_keep_script_lines, "unknown")

test/ruby/test_rubyvm.rb

@@ -32,6 +32,7 @@ class TestRubyVM < Test::Unit::TestCase
   end
 
   def test_keep_script_lines
+    omit if compiling_with_prism?
     pend if ENV['RUBY_ISEQ_DUMP_DEBUG'] # TODO
 
     prev_conf = RubyVM.keep_script_lines
@@ -68,4 +69,12 @@ class TestRubyVM < Test::Unit::TestCase
   ensure
     RubyVM.keep_script_lines = prev_conf
   end
+
+  private
+
+  # RubyVM.keep_script_lines does not mean anything in the context of prism, so
+  # we should omit tests that are looking for that functionality.
+  def compiling_with_prism?
+    RubyVM::InstructionSequence.compile("").to_a[4][:parser] == :prism
+  end
 end