Merge "Use fixed timestamp in img files using an environment variable" into main

$(hide) echo "root_dir=$(TARGET_ROOT_OUT)" >> $(1)

$(if $(filter true,$(PRODUCT_USE_DYNAMIC_PARTITION_SIZE)),\

    $(hide) echo "use_dynamic_partition_size=true" >> $(1))

$(if $(COPY_IMAGES_FOR_TARGET_FILES_ZIP),\

$(if $(USE_FIXED_TIMESTAMP_IMG_FILES)$(COPY_IMAGES_FOR_TARGET_FILES_ZIP),\

    $(hide) echo "use_fixed_timestamp=true" >> $(1))

$(if $(3),$(hide) $(foreach kv,$(3),echo "$(kv)" >> $(1);))

$(hide) sort -o $(1) $(1)