Move booting to RubyXCompiler init

Also pass the source into the compile method.
This way compiler can be reused for subsequent compile.
Does remove some double boots, but no major time save

test/risc/test_linker1.rb

@@ -3,9 +3,8 @@ require_relative "helper"
 module Risc
   class TestMachinePos < MiniTest::Test
     def setup
-      Parfait.boot!
-      Risc.boot!
-      @linker = RubyX::RubyXCompiler.new("class Space; def main(arg);a = 1;return a;end;end").ruby_to_risc(:arm)
+      code = "class Space; def main(arg);a = 1;return a;end;end"
+      @linker = RubyX::RubyXCompiler.new.ruby_to_risc(code,:arm)
       @linker.position_all
     end
     def test_positions_set