extract_utils.sh: Disable dex preopt on prebuilt apks

Change-Id: I230f1a8bb95cbc1df36bc652b03e58829ec278f5
diff --git a/build/tools/extract_utils.sh b/build/tools/extract_utils.sh
index fb7602b..e6951d6 100644
--- a/build/tools/extract_utils.sh
+++ b/build/tools/extract_utils.sh
@@ -282,6 +282,9 @@
         fi
         printf 'LOCAL_MODULE_TAGS := optional\n'
         printf 'LOCAL_MODULE_CLASS := %s\n' "$CLASS"
+        if [ "$CLASS" = "APPS" ]; then
+            printf 'LOCAL_DEX_PREOPT := false\n'
+        fi
         if [ ! -z "$EXTENSION" ]; then
             printf 'LOCAL_MODULE_SUFFIX := .%s\n' "$EXTENSION"
         fi