Spelling fixes e to i.

tests/language_strong/if_null_behavior_test.dart

Index: tests/language_strong/if_null_behavior_test.dart
diff --git a/tests/language_strong/if_null_behavior_test.dart b/tests/language_strong/if_null_behavior_test.dart
index 206fc3a25d8112d60ece641fb42b2e16c3d5bc81..c871c4e23fd107050e1722ad58ff330ad3b89435 100644
--- a/tests/language_strong/if_null_behavior_test.dart
+++ b/tests/language_strong/if_null_behavior_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).  The
 // static type of e is the least upper bound of the static type of e1 and the
 // static type of e2.