Address comments base on review

Change function name to ssl_session_set_hostname()
Remove hostname_len
Change hostname to c_string
Update test cases to multi session tickets

Signed-off-by: Xiaokang Qian <xiaokang.qian@arm.com>
diff --git a/tests/ssl-opt.sh b/tests/ssl-opt.sh
index 2a63610..2be5506 100755
--- a/tests/ssl-opt.sh
+++ b/tests/ssl-opt.sh
@@ -12879,7 +12879,7 @@
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_DEBUG_C
 run_test    "TLS 1.3: NewSessionTicket: servername check, m->m" \
-            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=1 \
+            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=4 \
             sni=localhost,data_files/server2.crt,data_files/server2.key,-,-,-,polarssl.example,data_files/server1-nospace.crt,data_files/server1.key,-,-,-" \
             "$P_CLI debug_level=4 server_name=localhost reco_mode=1 reconnect=1" \
             0 \
@@ -12901,7 +12901,7 @@
 requires_config_enabled MBEDTLS_SSL_CLI_C
 requires_config_enabled MBEDTLS_DEBUG_C
 run_test    "TLS 1.3: NewSessionTicket: servername negative check, m->m" \
-            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=1 \
+            "$P_SRV debug_level=4 crt_file=data_files/server5.crt key_file=data_files/server5.key force_version=tls13 tickets=4 \
             sni=localhost,data_files/server2.crt,data_files/server2.key,-,-,-,polarssl.example,data_files/server1-nospace.crt,data_files/server1.key,-,-,-" \
             "$P_CLI debug_level=4 server_name=localhost rec_server_name=remote reco_mode=1 reconnect=1" \
             1 \