[ARM][Testsuite]make dump_stack function call conditional in cold-lc.c

After r249013, die () and dump_stack () are both in cold section. This makes
the compiler generate bl instruction for the function call, instead of
honoring the -mlong-calls option.

This patch changes the dump_stack function call conditional, which fixes the
regression.

gcc/testsuite/

	* gcc.target/arm/cold-lc.c: Update coding style, call dump_stack
	conditionally.

From-SVN: r249157

gcc/testsuite/ChangeLog

+2017-06-13  Renlin Li  <renlin.li@arm.com>
+
+	* gcc.target/arm/cold-lc.c: Update coding style, call dump_stack
+	conditionally.
+
 2017-06-13  Martin Jambor  <mjambor@suse.cz>
 
 	PR tree-optimization/80803

gcc/testsuite/gcc.target/arm/cold-lc.c

@@ -11,13 +11,14 @@ extern int show_stack (struct task_struct *, unsigned long *);
 
 void dump_stack (void)
 {
-    unsigned long stack;
-    show_stack ((current_thread_info ()->task), &stack);
+  unsigned long stack;
+  show_stack ((current_thread_info ()->task), &stack);
 }
 
 void die (char *str, void *fp, int nr)
 {
+  if (nr)
     dump_stack ();
-    while (1);
+  while (1);
 }