[Courgette] Refactor: Add and use Instruction*Receptor classes; call ParseFile() in 2 passes.

courgette/disassembler_win32_x86.h

Index: courgette/disassembler_win32_x86.h
diff --git a/courgette/disassembler_win32_x86.h b/courgette/disassembler_win32_x86.h
index 09fc888a0df0793161392f8f5d53a0dc3b59f363..d73d4063e1929eb18069ea632ba4b9f282a8e18d 100644
--- a/courgette/disassembler_win32_x86.h
+++ b/courgette/disassembler_win32_x86.h
@@ -16,6 +16,7 @@
 namespace courgette {
 
 class AssemblyProgram;
+class InstructionReceptor;
 
 class DisassemblerWin32X86 : public DisassemblerWin32 {
  public:
@@ -40,7 +41,7 @@ class DisassemblerWin32X86 : public DisassemblerWin32 {
   // DisassemblerWin32 interfaces.
   void ParseRel32RelocsFromSection(const Section* section) override;
   int AbsVAWidth() const override { return 4; }
-  CheckBool EmitAbs(Label* label, AssemblyProgram* program) override;
+  CheckBool EmitAbs(Label* label, InstructionReceptor* receptor) const override;
   bool SupportsRelTableType(int type) const override {
     return type == 3;  // IMAGE_REL_BASED_HIGHLOW
   }