Rebuild recovery-from-boot patch when calling add_img_to_target_files.

When using Verified Boot 2.0, releasetools specifies a salt value based
on build fingerprint, so that to give idempotent images.

However, the change that removed static `ro.build.fingerprint` [1] broke
the behavior, as common.LoadInfoDict still relies on fingerprints.
Without a fixed salt, the first call to make_recovery_patch.py and the
second one (which writes IMAGES/{boot,recovery}.img) will see different
images, which leads to install-recovery.sh failure.

Note that currently there's a dependency that requires getting bootable
images through two separate calls. make_recovery_patch.py has to happen
first to get (placeholder) files in the system image. We then generate
canned fs_config files, and finally use add_img_to_target_files.py to
write the images.

This CL adds a quick workaround to force rebuilding the
recovery-from-boot patch while calling add_img_to_target_files.py.

[1] https://android-review.googlesource.com/c/platform/build/+/892933

Bug: 134123803
Bug: 134525174
Test: TreeHugger
Test: Build a non-A/B target that uses AVB. Run validate_target_files.py
      on the generated target_files.zip.
Change-Id: I5859e30be63bfd54398cf41fd2d907f15285f560
Merged-In: I5859e30be63bfd54398cf41fd2d907f15285f560
(cherry picked from commit 4978fa99d1)

core/Makefile

@@ -4175,8 +4175,9 @@ ifneq ($(BOARD_SUPER_PARTITION_GROUPS),)
 	    $(if $(_group_partition_list), \
 	        echo "$(group)_partition_list=$(_group_partition_list)" >> $(zip_root)/META/dynamic_partitions_info.txt;))
 endif # BOARD_SUPER_PARTITION_GROUPS
+	@# TODO(b/134525174): Remove `-r` after addressing the issue with recovery patch generation.
 	$(hide) PATH=$(foreach p,$(INTERNAL_USERIMAGES_BINARY_PATHS),$(p):)$$PATH MKBOOTIMG=$(MKBOOTIMG) \
-	    build/make/tools/releasetools/add_img_to_target_files -a -v -p $(HOST_OUT) $(zip_root)
+	    build/make/tools/releasetools/add_img_to_target_files -a -r -v -p $(HOST_OUT) $(zip_root)
 	@# Zip everything up, preserving symlinks and placing META/ files first to
 	@# help early validation of the .zip file while uploading it.
 	$(hide) find $(zip_root)/META | sort >$@.list

tools/releasetools/add_img_to_target_files.py

@@ -28,7 +28,8 @@ Usage:  add_img_to_target_files [flag] target_files
 
   -r  (--rebuild_recovery)
       Rebuild the recovery patch and write it to the system image. Only
-      meaningful when system image needs to be rebuilt.
+      meaningful when system image needs to be rebuilt and there're separate
+      boot / recovery images.
 
   --replace_verity_private_key
       Replace the private key used for verity signing. (same as the option
@@ -153,7 +154,8 @@ def AddSystem(output_zip, recovery_img=None, boot_img=None):
       else:
         common.ZipWrite(output_zip, ofile.name, arc_name)
 
-  if OPTIONS.rebuild_recovery:
+  if (OPTIONS.rebuild_recovery and recovery_img is not None and
+      boot_img is not None):
     logger.info("Building new recovery patch")
     common.MakeRecoveryPatch(OPTIONS.input_tmp, output_sink, recovery_img,
                              boot_img, info_dict=OPTIONS.info_dict)