[stable-2.7] Mark AWS credentials in ansible-test as sensitive.

This avoids displaying the credentials in CI when retrying tests at maximum verbosity.
(cherry picked from commit b73e772)

Co-authored-by: Matt Clay <matt@mystile.com>

test/runner/lib/cloud/aws.py

@@ -71,6 +71,9 @@ class AwsCloudProvider(CloudProvider):
                 REGION='us-east-1',
             )
 
+            display.sensitive.add(values['SECRET_KEY'])
+            display.sensitive.add(values['SECURITY_TOKEN'])
+
             config = self._populate_config_template(config, values)
 
         self._write_config(config)