manifest: update to 9.0.0_r44

Change-Id: I5d5f52401446870fc2cf8a035cfea9ee91b34b5f

default.xml

@@ -4,7 +4,7 @@
   <remote  name="aosp"
            fetch="https://android.googlesource.com"
            review="https://android-review.googlesource.com/" />
-  <default revision="refs/tags/android-9.0.0_r40"
+  <default revision="refs/tags/android-9.0.0_r44"
            remote="aosp"
            sync-c="true"
            sync-j="12" />