Spelling fixes e to i.

tests/language/if_null_evaluation_order_test.dart

Index: tests/language/if_null_evaluation_order_test.dart
diff --git a/tests/language/if_null_evaluation_order_test.dart b/tests/language/if_null_evaluation_order_test.dart
index 5cfc26443959ad6ba8741e0e46464338b8031785..f5db1c259c44d13cc9fb283f3ea86588805ee94c 100644
--- a/tests/language/if_null_evaluation_order_test.dart
+++ b/tests/language/if_null_evaluation_order_test.dart
@@ -2,7 +2,7 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
-// Evaluation of an if-null expresion e of the form e1 ?? e2 is equivalent to
+// Evaluation of an if-null expression e of the form e1 ?? e2 is equivalent to
 // the evaluation of the expression ((x) => x == null ? e2 : x)(e1).
 //
 // Therefore, e1 should be evaluated first; if it is non-null, e2 should not