[images] Add argument to have QEMU-related images added to build archives.

Bug: BLD-461
Change-Id: I720d29f5f201d4efa8aa9e41853008c9952ad948
diff --git a/build/images/BUILD.gn b/build/images/BUILD.gn
index 2ad8b3b..680b231 100644
--- a/build/images/BUILD.gn
+++ b/build/images/BUILD.gn
@@ -44,6 +44,10 @@
   vbmeta_r_partition = ""
   active_partition = ""
   signed_image = false
+
+  # Whether to include images necessary to run Fuchsia in QEMU in build
+  # archives.
+  add_qemu_to_build_archives = false
 }
 
 assert(
@@ -498,6 +502,7 @@
     json = {
       name = "qemu-kernel"
       type = "kernel"
+      archive = add_qemu_to_build_archives
     }
     sdk = "qemu-kernel.bin"
     deps = []
@@ -884,6 +889,7 @@
     json = {
       name = "storage-full"
       type = "blk"
+      archive = add_qemu_to_build_archives
     }
     sdk = "fvm.blk"
     public = [