TestHeaderMapImplBase: avoid virtual call during construction (#10121)
TestHeaderMapImplBase: avoid virtual call during construction (#10121)

Signed-off-by: Otto van der Schaaf <f82e1104fcd8bfffc72e7185709f7902b0b97ebf@we-amp.com>
envoyproxy/envoy-wasm,eklitzke/envoy,istio/envoy,envoyproxy/envoy,lyft/envoy,lizan/envoy,envoyproxy/envoy-wasm,istio/envoy,envoyproxy/envoy-wasm,eklitzke/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy,istio/envoy,lyft/envoy,lyft/envoy,eklitzke/envoy,lizan/envoy,envoyproxy/envoy,lyft/envoy,eklitzke/envoy,lizan/envoy,lizan/envoy,envoyproxy/envoy,istio/envoy,istio/envoy,istio/envoy,envoyproxy/envoy,lyft/envoy,eklitzke/envoy,istio/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy-wasm,eklitzke/envoy,envoyproxy/envoy,lyft/envoy,lizan/envoy,envoyproxy/envoy