wrong extractor is appended to BoundaryExtractor

[git4azure]

https://github.com/Blazemeter/taurus/blob/ced9f031b1b3dba9d1dc4195558eb1522ac3be38/bzt/jmx/base.py#L1005C10-L1005C10

def _get_boundary_extractor(varname, subject, left, right, match_no, defvalue='NOT_FOUND', scope='', from_var=''):
....
subject = subjects.get(subject)
element = etree.Element("BoundaryExtractor", guiclass="BoundaryExtractorGui",
testclass="BoundaryExtractor", testname="Get %s" % varname, enabled="true")
element.append(JMX._string_prop("BoundaryExtractor.useHeaders", subject))
element.append(JMX._string_prop("BoundaryExtractor.refname", varname))
element.append(JMX._string_prop("BoundaryExtractor.lboundary", left))
element.append(JMX._string_prop("BoundaryExtractor.rboundary", right))
element.append(JMX._string_prop("RegexExtractor.default", defvalue))
element.append(JMX._string_prop("RegexExtractor.match_number", match_no))
element.extend(JMX.get_scope_props(scope, from_var))