Add the display/vblankphase and ctrl/peekcost tests

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>

test.py

@@ -200,12 +200,14 @@ tests_good = [
   "ctrl/sampling/sampling",
   "ctrl/sampling2/sampling2",
   "ctrl/vblank",
+  "ctrl/peekcost",
   "display/display",
   "display/hcount",
   "display/vblankmulti",
   "display/isstate",
   "display/setframebuf",
   "display/setmode",
+  "display/vblankphase",
   "dmac/dmactest",
   "font/altcharcode",
   "font/charglyphimage",