Make PRODUCT_BOOT_JARS and PRODUCT_UPDATABLE_BOOT_JARS disjoint.

This is to unify boot jars with system server jars:
PRODUCT_SYSTEM_SERVER_JARS and PRODUCT_UPDATABLE_SYSTEM_SERVER_JARS
do not overlap.

Test: aosp_walleye-userdebug boots

Exempt-From-Owner-Approval: cherry-pick.
Bug: 146363577
Change-Id: If001049a46f8e9d38921dabeedbd61e971ebfe73
Merged-In: If001049a46f8e9d38921dabeedbd61e971ebfe73
(cherry picked from commit ef4358e536ec3e40843759a203af3043704b7357)
diff --git a/android/variable.go b/android/variable.go
index 58e5940..e4a3fa3 100644
--- a/android/variable.go
+++ b/android/variable.go
@@ -230,7 +230,8 @@
 	UncompressPrivAppDex             *bool    `json:",omitempty"`
 	ModulesLoadedByPrivilegedModules []string `json:",omitempty"`
 
-	BootJars []string `json:",omitempty"`
+	BootJars          []string `json:",omitempty"`
+	UpdatableBootJars []string `json:",omitempty"`
 
 	IntegerOverflowExcludePaths []string `json:",omitempty"`