Sort PRODUCT_APEX_BOOT_JARS automatically.

This is a follow-up CL for https://r.android.com/1900565.

This is needed because product makefiles may need to add their own
APEX boot jars, and they cannot insert them in the correct alphabetical
order on the list. So it needs to be sorted automatically. Do this
after processing all product makefiles and populating the variable,
but before passing it to Soong.

Bug: 207474880
Test: lunch aosp_cf_x86_64_phone-userdebug && launch_cvd
      # cuttlefish device boots successfully
Change-Id: I86b58ef8aeac595e401d872f59a2936a67bedeec
diff --git a/core/product_config.mk b/core/product_config.mk
index cf92924..ae0efe2 100644
--- a/core/product_config.mk
+++ b/core/product_config.mk
@@ -320,10 +320,11 @@
 
 PRODUCT_SYSTEM_SERVER_JARS := $(call qualify-platform-jars,$(PRODUCT_SYSTEM_SERVER_JARS))
 
-# Sort APEX system server jars. We use deterministic alphabetical order when
-# constructing SYSTEMSERVERCLASSPATH definition on device after a Mainline
-# update. Enforce it in the build system as well to avoid recompiling everything
-# after an update due a change in SYSTEMSERVERCLASSPATH order.
+# Sort APEX boot and system server jars. We use deterministic alphabetical order
+# when constructing BOOTCLASSPATH and SYSTEMSERVERCLASSPATH definition on device
+# after an update. Enforce it in the build system as well to avoid recompiling
+# everything after an update due a change in the order.
+PRODUCT_APEX_BOOT_JARS := $(sort $(PRODUCT_APEX_BOOT_JARS))
 PRODUCT_APEX_SYSTEM_SERVER_JARS := $(sort $(PRODUCT_APEX_SYSTEM_SERVER_JARS))
 
 ifndef PRODUCT_SYSTEM_NAME
diff --git a/target/product/default_art_config.mk b/target/product/default_art_config.mk
index 5e20218..e988d00 100644
--- a/target/product/default_art_config.mk
+++ b/target/product/default_art_config.mk
@@ -65,7 +65,7 @@
     com.android.tethering:framework-tethering \
     com.android.wifi:framework-wifi
 
-# APEX system server jars. The list will be sorted automatically.
+# APEX system server jars. Keep the list sorted by module names and then library names.
 PRODUCT_APEX_SYSTEM_SERVER_JARS := \
     com.android.appsearch:service-appsearch \
     com.android.art:service-art \