[gdb/testsuite] Be more verbose about abort in gdb_breakpoint

I noticed that an abort when setting a breakpoint does not result in more
than:
...
(gdb) break 27^M
FAIL: gdb.a/b.exp: setting breakpoint at 27 (eof)
...

Handle this more verbosely, as is done in gdb_test_multiple, such that we have
instead:
...
(gdb) break 27^M
ERROR: GDB process no longer exists
GDB process exited with wait status 29309 exp9 0 0 CHILDKILLED SIGABRT SIGABRT
UNRESOLVED: gdb.a/b.exp: setting breakpoint at 27 (eof)
...

Tested on x86_64-linux.

gdb/testsuite/ChangeLog:

2020-10-16  Tom de Vries  <tdevries@suse.de>

	* lib/gdb.exp (gdb_breakpoint): Handle eof as in gdb_test_multiple.

1 files changed, 4 insertions, 0 deletions

diff --git a/gdb/testsuite/lib/gdb.exp b/gdb/testsuite/lib/gdb.exp
index 63ba800..ed647c9 100644
--- a/gdb/testsuite/lib/gdb.exp
+++ b/gdb/testsuite/lib/gdb.exp
@@ -565,6 +565,10 @@ proc gdb_breakpoint { function args } {
 		return 0
 	}
 	eof {
+		perror "GDB process no longer exists"
+		global gdb_spawn_id
+		set wait_status [wait -i $gdb_spawn_id]
+		verbose -log "GDB process exited with wait status $wait_status"
 		if { $print_fail } {
 			fail "$test_name (eof)"
 		}