Add is*() functions for more types.

Test: compiles
Change-Id: Ibeba6c814ac17192481935a067b7c835c4008dc7
diff --git a/ScalarType.h b/ScalarType.h
index d1e40b5..0ff8ec5 100644
--- a/ScalarType.h
+++ b/ScalarType.h
@@ -39,6 +39,8 @@
 
     ScalarType(Kind kind);
 
+    bool isScalar() const override;
+
     const ScalarType *resolveToScalarType() const override;
 
     std::string typeName() const override;