remap plugin question when pristine_host_hdr is enabled

[Conan]

In proxy/http/remap/RemapPlugins.cc, line 147 say "plugin did not
change host, port or path, copying from mapping rule"  when
TSRemapDoRemap return TSREMAP_NO_REMAP or TSREMAP_NO_REMAP_STOP.

If url_remap.pristine_host_hdr is enabled, I think host should not be
copied(changed). This affects mapFromUrl/requestUrl of
TSRemapRequestInfo. In a remap plugin chain, second plugin will get a
"copied" Url if first plugin return TSREMAP_NO_REMAP, which maybe not
reasonable.