[gdb] Move stack frame up to frame above V8_Fatal

UNREACHABLE and CHECK call V8_Fatal directly so treat them like
V8_Dcheck, but also ensure that the frame is moved up to the DCHECK
frame even if it calls V8_Fatal.

Change-Id: Iad5f2e3ea95182bed473d6b2d843a0c1e111911d
Reviewed-on: https://chromium-review.googlesource.com/1183303Reviewed-by: Leszek Swirski <leszeks@chromium.org>
Commit-Queue: Dan Elphick <delphick@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55267}

tools/gdbinit

@@ -130,14 +130,15 @@ python
 def dcheck_stop_handler(event):
   orig_frame = gdb.selected_frame()
   frame = orig_frame
+  select_frame = None
   while frame is not None:
-    if frame.name() == 'V8_Dcheck':
+    if frame.name() in ('V8_Dcheck', 'V8_Fatal'):
       select_frame = frame.older()
-      if select_frame is not None:
-        select_frame.select()
-        gdb.execute('frame')
-        break
     frame = frame.older()
 
+  if select_frame is not None:
+    select_frame.select()
+    gdb.execute('frame')
+
 gdb.events.stop.connect(dcheck_stop_handler)
 end