bootstd: Add vbe bootmeth into sandbox

Update sandbox to include the VBE bootmeth. Update a few existing tests to
take account of this change, specifically that the new bootmeth now
appears when scanning.

Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/test/boot/Makefile b/test/boot/Makefile
index 1730792..9e9d5ae 100644
--- a/test/boot/Makefile
+++ b/test/boot/Makefile
@@ -3,3 +3,7 @@
 # Copyright 2021 Google LLC
 
 obj-$(CONFIG_BOOTSTD) += bootdev.o bootstd_common.o bootflow.o bootmeth.o
+
+ifdef CONFIG_OF_LIVE
+obj-$(CONFIG_BOOTMETH_VBE_SIMPLE) += vbe_simple.o
+endif