build: add libicu i18n support

Adds a --with-icu-path= switch to the configure script.  Requires that
the user checks out the copy of libicu that's bundled with chromium to
a fixed directory.  It's still a little rough around the edges but it
works.

Fixes #6371.
tls: fix handling of asterisk in SNI context

Wildcard server names should not match subdomains.

Quote from RFC2818:

   ...Names may contain the wildcard
   character * which is considered to match any single domain name
   component or component fragment. E.g., *.a.com matches foo.a.com but
   not bar.foo.a.com. f*.com matches foo.com but not bar.com.

fix #6610
openssl: add assembly for aes and gcm
benchmark: fixate `ciphers` in tls benchmarks

Benchmark should always use the same cipher in order to be truthful.