MDEV-16708: disabled the test main.sp to be executed with ps-protocol

This test has been disable by the reason that it contains multi-statements
that not supported in PS mode. Unfortunately, some of these multi-statements
can't be converted to a sequence of single-statements by the reason that
multi-statementness is a requirement for tests (e.g. tests for
the MySQL bugs #5307, #8762) therefore the whole test file will be
skipped in case it is run with --ps-protocol

mysql-test/main/sp.test

@@ -15,6 +15,11 @@
 # Tests that require multibyte character sets, which are not always available,
 #   go into separate files (e.g. sp-ucs2.test)
 
+if (`SELECT $PS_PROTOCOL != 0`)
+{
+   --skip Need regular protocol but ps-protocol was specified
+}
+
 --source include/default_charset.inc
 set @save_character_set_client=@@character_set_client;
 set @save_userstat=@@global.userstat, @@global.userstat= 0;