Add option to allow product makefiles to skip building super_empty.img

This change doesn't change the condition for building super_empty.img,
it just add a toggle PRODUCT_BUILD_SUPER_EMPTY_IMAGE that product
makefiles can use to skip building super_empty.img.
Products that don't use super_empty at all, for example GSI, can set
this option to ensure the super_empty.img is not built.

Bug: 183068624
Test: "m dist" on GSI and check the build artifacts under OUT and DIST
  directories, and check the contents of *-img-*.zip
Change-Id: I54943952873d2d297fd9d18cbe14742bc12ae9c6
diff --git a/tools/releasetools/add_img_to_target_files.py b/tools/releasetools/add_img_to_target_files.py
index 900c7b5..4fe10c6 100644
--- a/tools/releasetools/add_img_to_target_files.py
+++ b/tools/releasetools/add_img_to_target_files.py
@@ -1027,8 +1027,9 @@
       AddVBMeta(output_zip, partitions, "vbmeta", vbmeta_partitions)
 
   if OPTIONS.info_dict.get("use_dynamic_partitions") == "true":
-    banner("super_empty")
-    AddSuperEmpty(output_zip)
+    if OPTIONS.info_dict.get("build_super_empty_partition") == "true":
+      banner("super_empty")
+      AddSuperEmpty(output_zip)
 
   if OPTIONS.info_dict.get("build_super_partition") == "true":
     if OPTIONS.info_dict.get(