LPBUG#886526: Add propoer shebang to scripts

mysql-test/t/long_tmpdir-master.sh

@@ -1,3 +1,4 @@
+#!/bin/sh
 d="$MYSQLTEST_VARDIR/tmp/long_temporary_directory_path_123456789_123456789_123456789_123456789_123456789_123456789_123456789_123456789"
 test -d "$d" || mkdir "$d"
 rm -f "$d"/*

mysql-test/t/lowercase_mixed_tmpdir-master.sh

@@ -1,3 +1,4 @@
+#!/bin/sh
 # This test requires a non-lowercase tmpdir directory on a case-sensitive
 # filesystem.
 

sql-bench/graph-compare-results.sh

@@ -1,3 +1,4 @@
+#!/usr/bin/perl
 ####
 #### Hello ... this is a heavily hacked script by Luuk 
 #### instead of printing the result it makes a nice gif