Correctly recognize external strings.

src/objects-inl.h

Index: src/objects-inl.h
diff --git a/src/objects-inl.h b/src/objects-inl.h
index dd3c0b182d616fda37b0c66d24acba52e2593570..4b51fa3d9f9d2e3bf20d1bbf8a515aa63d74ff68 100644
--- a/src/objects-inl.h
+++ b/src/objects-inl.h
@@ -433,9 +433,6 @@ bool StringShape::IsExternalAscii() {
 }
 
 
-STATIC_CHECK((kExternalStringTag | kOneByteStringTag) ==
-             Internals::kExternalAsciiRepresentationTag);
-
 STATIC_CHECK(v8::String::ASCII_ENCODING == kOneByteStringTag);
 
 
@@ -444,6 +441,13 @@ bool StringShape::IsExternalTwoByte() {
 }
 
 
+STATIC_CHECK(kConsStringTag == Internals::kConsRepresentationTag);
+
+STATIC_CHECK((kConsStringTag | kTwoByteStringTag) ==
+             Internals::kConsTwoByteRepresentationTag);
+
+STATIC_CHECK(kExternalStringTag == Internals::kExternalRepresentationTag);
+
 STATIC_CHECK((kExternalStringTag | kTwoByteStringTag) ==
              Internals::kExternalTwoByteRepresentationTag);