HTTP header fields are not treated case insensitive in SwitchYard JUnit tests

Issue

As stated in https://www.w3.org/Protocols/rfc2616/rfc2616-sec4.html#sec4.2:

Each header field consists of a name followed by a colon (":") and the field value. Field names are case-insensitive.

When running a SwitchYard application in EAP, we noticed that all HTTP header field names are mapped into SwitchYard/Camel context in lower case. Only by targeting the lower case field names, the headers can be retrieved.

When running the same SwitchYard application in a JUnit test, however, then this conversion to lower case is missing. This leads to different behavior and thus confusion if fields are added to the http header in camel case.