Revert "Null check remover understands JS fragments."

pkg/compiler/lib/src/js/js.dart

Index: pkg/compiler/lib/src/js/js.dart
diff --git a/pkg/compiler/lib/src/js/js.dart b/pkg/compiler/lib/src/js/js.dart
index 7cf2873ff03f4527d5e5e19a05265a3303744ade..1a08cfbeb0798072ea178fd3993b134183c5c718 100644
--- a/pkg/compiler/lib/src/js/js.dart
+++ b/pkg/compiler/lib/src/js/js.dart
@@ -162,27 +162,4 @@ class UnparsedNode extends DeferredString
 
   @override
   String get value => _literal.value;
-}
-
-/// Returns `true` if [template] will immediately give a TypeError if the first
-/// placeholder is `null` or `undefined`.
-bool isNullGuardOnFirstArgument(Template template) {
-  // We look for a template of the form
-  //
-  //     #.something
-  //     #.something()
-  //
-  Node node = template.ast;
-  if (node is Call) {
-    Call call = node;
-    node = node.target;
-  }
-  if (node is PropertyAccess) {
-    PropertyAccess access = node;
-    if (access.receiver is InterpolatedExpression) {
-      InterpolatedExpression hole = access.receiver;
-      return hole.isPositional && hole.nameOrPosition == 0;
-    }
-  }
-  return false;
-}
+}