fixes for make check with --enable-all (now including --enable-earlydata) with fips or asynccrypt:

in scripts/tls13.test, use fips-compatible server-side cipher suite for "TLS v1.3 cipher suite mismatch" test, and modernize some syntax;

in configure.ac, omit earlydata from enable-all when asynccrypt, pending fix;

also in configure.ac, fix AC_CHECK_DECLS()-overriding-AC_CHECK_FUNCS() kludge, to fix CPPFLAGS=-std=c99 builds.