Add support for unless

ifs without a true branch would crash before
Somewhat more verbose but unified

test/vool/test_if_statement.rb

@@ -0,0 +1,30 @@
+require_relative "helper"
+
+module Vool
+  class TestConditionIfMom < MiniTest::Test
+    include VoolCompile
+
+    def setup
+      Parfait.boot!(Parfait.default_test_options)
+      @compiler = compile_first_method( "if(5.div4) ; @a = 6 ; else; @a = 5 ; end")
+      @ins = @compiler.mom_instructions.next
+    end
+
+    def test_condition
+      assert_equal TruthCheck , @ins.next(4).class
+    end
+    def test_condition_is_slot
+      assert_equal SlotDefinition , @ins.next(4).condition.class , @ins
+    end
+    def test_hoisted_dynamic_call
+      assert_equal SimpleCall , @ins.next(2).class
+      assert_equal :div4 , @ins.next(2).method.name
+    end
+    def test_array
+      check_array [MessageSetup, ArgumentTransfer, SimpleCall, SlotLoad, TruthCheck,
+                  Label ,SlotLoad, Jump, Label, SlotLoad, Label,
+                  Label, ReturnSequence, Label ] , @ins
+    end
+
+  end
+end