Testsuite - Improve memory required to run test12.2

Running the test required more than 4GB of memory. This is quite a lot
and is not needed to properly test the functionality.

Bug 8318

testsuite/expect/test12.2

@@ -43,7 +43,7 @@ set job_id      0
 set matches     0
 
 # job parameters
-set mem_size    1048576
+set mem_size    102400
 set sleep_time  32
 set ret_code    42
 set file_size   10485760