testsuite: Fix gdb.base/bang.exp for remote stubs without exit

Some remote stubs do not have a proper exit() function implementation.
gdb.base/bang.exp was failing on those targets due to timeout.  With
this patch bang.exp uses already defined library procedures to handle
this situation gracefully without breaking native targets.

Tested with x86_64 (unix, native-gdbserver) and with arc-*-elf32.

gdb/testsuite/ChangeLog:

2013-10-25  Anton Kolesov  <Anton.Kolesov@synopsys.com>  (tiny change)

	* gdb.base/bang.exp: Use gdb_continue_to_end to properly support
	remote stubs where exit() behaviour is unreliable.

gdb/testsuite/ChangeLog

@@ -1,3 +1,8 @@
+2013-10-25  Anton Kolesov  <Anton.Kolesov@synopsys.com>  (tiny change)
+
+	* gdb.base/bang.exp: Use gdb_continue_to_end to properly support
+	remote stubs where exit() behaviour is unreliable.
+
 2013-10-25  Pedro Alves  <palves@redhat.com>
 
 	* gdb.cp/m-static.exp: Adjust expected output of printing a

gdb/testsuite/gdb.base/bang.exp

@@ -26,12 +26,5 @@ if {[prepare_for_testing $testfile.exp ${testfile}! $srcfile \
 
 # Verify that we can run the program and that it terminates normally.
 
-gdb_run_cmd
-gdb_expect {
-    -re ".*$inferior_exited_re normally.*$gdb_prompt $" {
-        pass "run program"
-    }
-    timeout {
-	fail "run program (timeout)"
-    }
-}
+runto_main
+gdb_continue_to_end "" continue 1