let boot_functions return the compilers

methods are still added, but this is a good step to removing the risc/cpu level from the methods

test/risc/test_builtin.rb

@@ -0,0 +1,22 @@
+require_relative "helper"
+
+module Risc
+  class TestBuiltinFunction < MiniTest::Test
+
+    def setup
+      Parfait.boot!
+    end
+    def test_has_boot_function
+      assert Builtin.boot_functions
+    end
+    def test_boot_function_type
+      assert_equal Array, Builtin.boot_functions.class
+    end
+    def test_boot_function_length
+      assert_equal 23, Builtin.boot_functions.length
+    end
+    def test_boot_function_first
+      assert_equal RiscCompiler, Builtin.boot_functions.first.class
+    end
+  end
+end