Record ToBoolean's type information in Hydrogen's HBranch instruction, so we can use it in LCodeG...

src/type-info.h

Index: src/type-info.h
===================================================================
--- src/type-info.h	(revision 8735)
+++ src/type-info.h	(working copy)
@@ -238,6 +238,11 @@
 
   bool LoadIsBuiltin(Property* expr, Builtins::Name id);
 
+  // TODO(1571) We can't use ToBooleanStub::Types as the return value because
+  // of various cylces in our headers. Death to tons of implementations in
+  // headers!! :-P
+  byte ToBooleanTypes(unsigned ast_id);
+
   // Get type information for arithmetic operations and compares.
   TypeInfo UnaryType(UnaryOperation* expr);
   TypeInfo BinaryType(BinaryOperation* expr);