Create super_empty.img using Soong

The build rule for this .img file will be created in super_image. It
will use the a minimized file returned by `buildMiscInfo` without any
partition information. This file will be disted in target_files.zip

Bug: 390192334
Test: Verified that this file is bit-identical between make and soong
for aosp_cf_x86_64_phone

Change-Id: I9238d67d2ca8739064509a858d5251f2641896e9
diff --git a/filesystem/android_device.go b/filesystem/android_device.go
index 22ad7cf..45a8620 100644
--- a/filesystem/android_device.go
+++ b/filesystem/android_device.go
@@ -623,6 +623,10 @@
 					builder.Command().Textf("cp ").Input(info.SubImageInfo[partition].MapFile).Textf(" %s/IMAGES/", targetFilesDir.String())
 				}
 			}
+			// super_empty.img
+			if info.SuperEmptyImage != nil {
+				builder.Command().Textf("cp ").Input(info.SuperEmptyImage).Textf(" %s/IMAGES/", targetFilesDir.String())
+			}
 		} else {
 			ctx.ModuleErrorf("Super partition %s does set SuperImageProvider\n", superPartition.Name())
 		}