Update NSS to 3.38

- Added HACL*Poly1305 32-bit (INRIA/Microsoft)
- Updated to final TLS 1.3 draft version (28)
- Removed TLS 1.3 prerelease draft limit check
- Removed NPN code
- Enabled dev/urandom-only RNG on Linux with NSS_SEED_ONLY_DEV_URANDOM for non-standard environments
- Fixed several bugs with TLS 1.3 negotiation
- Updated internal certificate store
- Added support for the TLS Record Size Limit Extension.
- Fixed CVE-2018-0495
- Various security fixes in the ASN.1 code.

security/nss/gtests/ssl_gtest/ssl_custext_unittest.cc

@@ -68,6 +68,7 @@ static const uint16_t kManyExtensions[] = {
     ssl_next_proto_nego_xtn,
     ssl_renegotiation_info_xtn,
     ssl_tls13_short_header_xtn,
+    ssl_record_size_limit_xtn,
     1,
     0xffff};
 // The list here includes all extensions we expect to use (SSL_MAX_EXTENSIONS),