Add JS tests for global const equality.

Add these tests before fixing bug 419.

R=dsinclair@chromium.org

Review URL: https://codereview.chromium.org/1761923002 .
diff --git a/testing/resources/javascript/consts.in b/testing/resources/javascript/consts.in
index a717ec8..6fb8215 100644
--- a/testing/resources/javascript/consts.in
+++ b/testing/resources/javascript/consts.in
@@ -66,6 +66,16 @@
   }
 }
 
+function doEqualityTests() {
+  app.alert("String equality test (==): " +
+            (IDS_GREATER_THAN == IDS_GREATER_THAN));
+  app.alert("String equality test (===): " +
+            (IDS_GREATER_THAN === IDS_GREATER_THAN));
+  app.alert("Array equality test (==): " +
+            (RE_PHONE_COMMIT == RE_PHONE_COMMIT));
+  app.alert("Array equality test (===): " +
+            (RE_PHONE_COMMIT === RE_PHONE_COMMIT));
+}
 
 try {
   doTest("border", ["s", "b", "d", "i", "u", "nonesuch"]);
@@ -112,6 +122,7 @@
     "RE_SSN_COMMIT"
   ]);
 
+  doEqualityTests();
 } catch (e) {
   app.alert("ERROR: " + e.toString());
 }
diff --git a/testing/resources/javascript/consts_expected.txt b/testing/resources/javascript/consts_expected.txt
index 4476c62..a2d29a9 100644
--- a/testing/resources/javascript/consts_expected.txt
+++ b/testing/resources/javascript/consts_expected.txt
@@ -106,3 +106,7 @@
   \d{0,3}(\.|[- ])?\d{0,2}(\.|[- ])?\d{0,4}
 Alert: RE_SSN_COMMIT is
   \d{3}(\.|[- ])?\d{2}(\.|[- ])?\d{4}
+Alert: String equality test (==): true
+Alert: String equality test (===): true
+Alert: Array equality test (==): true
+Alert: Array equality test (===): true