Sentinel tests, disable FD leak check, and print more details (#8376)

* Print more details about fd leaks
* temporarily prevent the leaks from failing the tests

Co-authored-by: Oran Agra <oran@redislabs.com>

tests/instances.tcl

@@ -423,7 +423,8 @@ proc end_tests {} {
     if { [file exists $sentinel_fd_leaks_file] } {
         puts [colorstr red "WARNING: sentinel test(s) failed, there are leaked fds in sentinel:"] 
         puts [exec cat $sentinel_fd_leaks_file]
-        exit 1
+        # temporarily disabling this error from failing the tests until leaks are fixed.
+        #exit 1
     }
 
     if {$::failed == 0 } {

tests/sentinel/tests/includes/notify.sh

@@ -16,5 +16,6 @@ then
     if [ ! -f $sentinel_fd_leaks_file ]
     then
         ls -l /proc/self/fd | cat >> $sentinel_fd_leaks_file
+        lsof -p $$ | cat >> $sentinel_fd_leaks_file
     fi
 fi