tests: fix a compilation error. (#6521)
tests: fix a compilation error. (#6521)

Catch the CodecProtocolException by reference to fix the following
error when building tests:

test/common/http/http1/codec_impl_test.cc: In member function 'virtual void Envoy::Http::Http1::Http1ServerConnectionImplTest_HeaderMutateEmbeddedCRLF_Test::TestBody()':
test/common/http/http1/codec_impl_test.cc:347:16: error: catching polymorphic type 'class Envoy::Http::CodecProtocolException' by value [-Werror=catch-value=]
       } catch (CodecProtocolException) {
                ^~~~~~~~~~~~~~~~~~~~~~
cc1plus: all warnings being treated as errors

Signed-off-by: Ismo Puustinen <75dda586a9213f0e0695eb79120c94222bb30e60@intel.com>
eklitzke/envoy,eklitzke/envoy,eklitzke/envoy,lizan/envoy,envoyproxy/envoy,jrajahalme/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,lizan/envoy,dnoe/envoy,lyft/envoy,envoyproxy/envoy,istio/envoy,jrajahalme/envoy,envoyproxy/envoy,jrajahalme/envoy,lizan/envoy,envoyproxy/envoy,dnoe/envoy,istio/envoy,envoyproxy/envoy,eklitzke/envoy,jrajahalme/envoy,dnoe/envoy,lizan/envoy,lyft/envoy,envoyproxy/envoy,istio/envoy,dnoe/envoy,envoyproxy/envoy-wasm,eklitzke/envoy,lizan/envoy,istio/envoy,envoyproxy/envoy-wasm,istio/envoy,jrajahalme/envoy,lizan/envoy,envoyproxy/envoy-wasm,dnoe/envoy,jrajahalme/envoy,istio/envoy,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,envoyproxy/envoy-wasm,eklitzke/envoy,envoyproxy/envoy,lyft/envoy,lyft/envoy,lyft/envoy,istio/envoy