Reduce the amount of console "spam", by ignoring info/warn calls,…

… when running the unit-tests in Node.js/Travis

Compared to running the unit-tests in "regular" browsers, where any console output won't get mixed up with test output, in Node.js/Travis the test output looks quite noisy.
By ignoring `info`/`warn` calls, when running unit-tests in Node.js/Travis, the test output is a lot smaller not to mention that any *actual* failures are more easily spotted.

test/unit/clitests_helper.js

@@ -13,6 +13,7 @@
  * limitations under the License.
  */
 
+import { setVerbosityLevel, VerbosityLevel } from '../../src/shared/util';
 import isNodeJS from '../../src/shared/is_node';
 import { PDFNodeStream } from '../../src/display/node_stream';
 import { setPDFNetworkStreamFactory } from '../../src/display/api';
@@ -23,6 +24,10 @@ if (!isNodeJS()) {
                   'Node.js environments.');
 }
 
+// Reduce the amount of console "spam", by ignoring `info`/`warn` calls,
+// when running the unit-tests in Node.js/Travis.
+setVerbosityLevel(VerbosityLevel.ERRORS);
+
 // Set the network stream factory for the unit-tests.
 setPDFNetworkStreamFactory(function(params) {
   return new PDFNodeStream(params);