Fix null.runtimeType, reflect(null).type.superinterfaces, and reflect(null).getField.

sdk/lib/_internal/compiler/implementation/resolution/members.dart

Index: sdk/lib/_internal/compiler/implementation/resolution/members.dart
diff --git a/sdk/lib/_internal/compiler/implementation/resolution/members.dart b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
index 4ab41ca0c8b2f627d2196b02a7b7cbe60a7088b0..f97438cec143959f42c7e5ab2a689f85c6bf94c8 100644
--- a/sdk/lib/_internal/compiler/implementation/resolution/members.dart
+++ b/sdk/lib/_internal/compiler/implementation/resolution/members.dart
@@ -803,7 +803,7 @@ class ResolverTask extends CompilerTask {
       element.origin.ensureResolved(compiler);
       // Ensure that the type is computed.
       element.computeType(compiler);
-      // Copy class hiearchy from origin.
+      // Copy class hierarchy from origin.
       element.supertype = element.origin.supertype;
       element.interfaces = element.origin.interfaces;
       element.allSupertypesAndSelf = element.origin.allSupertypesAndSelf;