Issue #997: existing triple-shift tests corrected.

Author: iarkh

Language/Expressions/Shift/integer_t04.dart

@@ -11,17 +11,18 @@
  */
 // SharedOptions=--enable-experiment=triple-shift
 
+import "../../../Utils/expect.dart";
+
 main() {
   int i1 = 12345;
   int i2 = -11;
   int i3 = -12345;
 
-  var res1 = i1 >>> i2;    //# 01: compile-time error
-  var res2 = i1 >>> i3;    //# 02: compile-time error
-  var res3 = i2 >>> i3;    //# 03: compile-time error
-  var res4 = i3 >>> i2;    //# 04: compile-time error
-
-  var res5 = i1 >>> -2;    //# 05: compile-time error
-  var res6 = 2000 >>> i3;  //# 06: compile-time error
-  var res7 = 2000 >>> -14; //# 07: compile-time error
+  Expect.throws(() { i1 >>> i2; });
+  Expect.throws(() { i1 >>> i3; });
+  Expect.throws(() { i2 >>> i3; });
+  Expect.throws(() { i3 >>> i2; });
+  Expect.throws(() { i1 >>> -2; });
+  Expect.throws(() { 2000 >>> i3; });
+  Expect.throws(() { 150 >>> -14; });
 }

Language/Expressions/Shift/integer_t05.dart

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2019, the Dart project authors.  Please see the AUTHORS file
+ * 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.
+ */
+/**
+ * @assertion N/A
+ * @description Checks that triple right shift argument cannot be negative and
+ * cause compile time error if this is a constant expression (see co19 Issue
+ * #355 for more details)
+ * @author [email protected]
+ */
+// SharedOptions=--enable-experiment=triple-shift
+
+main() {
+  const int i1 = 12345;
+  const int i2 = -11;
+  const int i3 = -12345;
+
+  const res1 = i1 >>> i2;    //# 01: compile-time error
+  const res2 = i1 >>> i3;    //# 02: compile-time error
+  const res3 = i2 >>> i3;    //# 03: compile-time error
+  const res4 = i3 >>> i2;    //# 04: compile-time error
+
+  const res5 = i1 >>> -2;    //# 05: compile-time error
+  const res6 = 2000 >>> i3;  //# 06: compile-time error
+  const res7 = 2000 >>> -14; //# 07: compile-time error
+}

LanguageFeatures/nnbd/triple-shift/local_variable_read_A02_t03.dart

@@ -23,13 +23,13 @@ main() {
   if (b) {
     x = 42;
   }
-  x >>>= 2;
+  x  >>>= 2;
   Expect.equals(42 >>> 2, x);
 
   var y;
   b = false;
   if (b) {
     y = 42;
   }
-  Expect.throws(() {x >>>= 2;});
+  Expect.throws(() {y >>>= 2;});
 }