Last slice of fix for Bug#42003 tests missing the disconnect of connections <> default

+ Fix for Bug#43114 wait_until_count_sessions too restrictive, random PB failures
+ Removal of a lot of other weaknesses found
+ modifications according to review

mysql-test/t/ssl_compress.test

@@ -4,6 +4,9 @@
 -- source include/have_ssl.inc
 -- source include/have_compress.inc
 
+# Save the initial number of concurrent sessions
+--source include/count_sessions.inc
+
 connect (ssl_compress_con,localhost,root,,,,,SSL COMPRESS);
 
 # Check ssl turned on
@@ -20,3 +23,10 @@ SHOW STATUS LIKE 'Ssl_cipher';
 
 # Check compression turned on
 SHOW STATUS LIKE 'Compression';
+
+connection default;
+disconnect ssl_compress_con;
+
+# Wait till all disconnects are completed
+--source include/wait_until_count_sessions.inc
+