command line option in test suite to activate valgrind mode

tests/support/server.tcl

@@ -171,7 +171,7 @@ proc start_server {options {code undefined}} {
     set stderr [format "%s/%s" [dict get $config "dir"] "stderr"]
 
     if {$::valgrind} {
-        exec valgrind src/redis-server $config_file > $stdout 2> $stderr &
+        exec valgrind --suppressions=src/valgrind.sup src/redis-server $config_file > $stdout 2> $stderr &
     } else {
         exec src/redis-server $config_file > $stdout 2> $stderr &
     }

tests/test_helper.tcl

@@ -167,6 +167,8 @@ for {set j 0} {$j < [llength $argv]} {incr j} {
             }
         }
         incr j
+    } elseif {$opt eq {--valgrind}} {
+        set ::valgrind 1
     } elseif {$opt eq {--file}} {
         set ::file $arg
         incr j