DO NOT MERGE: Fix NPE bug in LocationManager

Both null and non-null GnssRequest objects may be present in the list of
requests to merge.

Bug: 165375330
Test: presubmits
Change-Id: I13284b1c32f1ad1fce39ad1ca2e4298194197015

location/java/android/location/LocationManager.java

@@ -3039,7 +3039,7 @@ public class LocationManager {
         protected GnssRequest merge(@NonNull List<GnssRequest> requests) {
             Preconditions.checkArgument(!requests.isEmpty());
             for (GnssRequest request : requests) {
-                if (request.isFullTracking()) {
+                if (request != null && request.isFullTracking()) {
                     return request;
                 }
             }