[es6] Initial steps towards a correct implementation of IsCallable.

src/hydrogen-instructions.h

Index: src/hydrogen-instructions.h
diff --git a/src/hydrogen-instructions.h b/src/hydrogen-instructions.h
index b524cfb2666383f454ca8dd42aadd51f07c1e0e8..7bfc509d7738a08a8899817c3e82d45fc45014ef 100644
--- a/src/hydrogen-instructions.h
+++ b/src/hydrogen-instructions.h
@@ -3628,6 +3628,7 @@ class HConstant final : public HTemplateInstruction<0> {
 
   bool HasBooleanValue() const { return type_.IsBoolean(); }
   bool BooleanValue() const { return BooleanValueField::decode(bit_field_); }
+  bool IsCallable() const { return IsCallableField::decode(bit_field_); }
   bool IsUndetectable() const {
     return IsUndetectableField::decode(bit_field_);
   }
@@ -3760,9 +3761,10 @@ class HConstant final : public HTemplateInstruction<0> {
   class IsNotInNewSpaceField : public BitField<bool, 5, 1> {};
   class BooleanValueField : public BitField<bool, 6, 1> {};
   class IsUndetectableField : public BitField<bool, 7, 1> {};
+  class IsCallableField : public BitField<bool, 8, 1> {};
 
   static const InstanceType kUnknownInstanceType = FILLER_TYPE;
-  class InstanceTypeField : public BitField<InstanceType, 8, 8> {};
+  class InstanceTypeField : public BitField<InstanceType, 16, 8> {};
 
   // If this is a numerical constant, object_ either points to the
   // HeapObject the constant originated from or is null.  If the