[Extensions Cleanup] Remove old js-bindings errors branches

One test still had handling for either js-bindings or native
bindings.  Since native bindings have been shipped for a long time,
remove the old js binding errors.

Bug: None
Change-Id: Ifa37068f9356c5d210593f068864b6efff3e0d20
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2336995Reviewed-by: David Bertoni <dbertoni@chromium.org>
Commit-Queue: Devlin <rdevlin.cronin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#795746}

extensions/test/data/api_test/printer_provider/request_capability/test.js

@@ -28,13 +28,8 @@ chrome.test.sendMessage('loaded', function(test) {
           }
 
           if (test == 'INVALID_VALUE') {
-            var jsBindingsError =
-                'Invalid value for argument 1. Expected \'object\'' +
-                ' but got \'string\'.';
-            var nativeBindingsError = 'No matching signature.';
-            var regexp =
-                new RegExp(nativeBindingsError + '|' + jsBindingsError);
-            chrome.test.assertThrows(callback, ['XXX'], regexp);
+            chrome.test.assertThrows(callback, ['XXX'],
+                                     'No matching signature.');
           } else if (test == 'EMPTY') {
             callback({});
           } else {