[PATCH] gdb.mi/mi-nonstop-exit.exp: fix racy test (PR testsuite/12649)

[Marek Polacek <mpolacek@redhat.com>]

I've changed the gdb_test_multiple to ugly send_gdb+gdb_expect, since 
we must not use the gdb_test_multiple (see PR 12647).  Here, I think,
it is not possible to use the mi_gdb_test, because mi_gdb_test either PASSes,
or FAILs, but in the `-gdb-show non-stop' test, we have to use the
`$expect_out' and possibly set the `supported' variable iff in the gdb output
is "supported=*".
Otherwise, if the output is just the "^done,value="off"", it is still OK, we
just don't use `$expect_out'.  Otherwise, this test FAILs.  That said, this
test never PASSes, it can only fail.

Using the send_gdb+gdb_expect in place of the gdb_test_multiple cures a race,
the problem is with the trailing ^M, as shown in PR 12647.

Thus, I propose this patch.  Tested with both read{,1}.  OK?

2011-05-17  Marek Polacek  <mpolacek@redhat.com>

        * gdb.mi/i-nonstop-exit.exp: Use the send_gdb+gdb_expect instead of
        the gdb_test_multiple.

--- gdb/gdb/testsuite/gdb.mi/mi-nonstop-exit.exp.mp     2011-01-01 16:33:47.000000000 +0100
+++ gdb/gdb/testsuite/gdb.mi/mi-nonstop-exit.exp        2011-05-17 20:32:52.708217970 +0200
@@ -37,13 +37,17 @@ mi_gdb_reinitialize_dir $srcdir/$subdir
 mi_gdb_load $binfile
 
 set supported 0
-gdb_test_multiple "-gdb-show non-stop" "" {
-    -re ".*\\^done,value=\"off\",supported=\"(\[^\"\]+)\"\r\n$mi_gdb_prompt$" {
+send_gdb "-gdb-show non-stop\n"
+gdb_expect {
+    -re "\\^done,value=\"off\",supported=\"(\[^\"\]+)\"\r\n$mi_gdb_prompt$" {
         if { $expect_out(1,string) == "1" } { 
             set supported 1
         }   
     }   
+    -re "\\^done,value=\"off\"\r\n$mi_gdb_prompt$" {
+    }
     -re ".*$mi_gdb_prompt$" {
+       fail "-gdb-show non-stop"
     }   
 }