Tests p:http-request: Error needs to be raised if value of header content-type is not correct.
Test ab-http-request-109.xml is expected to fail with error code err:XD0079 [XProc, Core steps].
It requires the following features: p:http-request.
<p:declare-step xmlns:err="http://www.w3.org/ns/xproc-error" xmlns:p="http://www.w3.org/ns/xproc" version="3.0">
<p:option name="WHOST" select="'http://localhost:8246'" static="true"/>
<p:output port="result"/>
<p:http-request href="{$WHOST}/service/fixed-xml" headers="map{'content-type' : 'surely-not-correct'}">
<p:with-input>
<p:empty/>
</p:with-input>
</p:http-request>
</p:declare-step>
Added static options for web server host and port.
Changed error code.
Added new tests for p:http-request.