gn2bp: Move the logic of source exclusion

Test: ./update_results.sh
Change-Id: Ic89cfc207e35cd2f90415fb888de8354ee190115
diff --git a/tools/gn2bp/Android.bp.swp b/tools/gn2bp/Android.bp.swp
index 247d896..7a26073 100644
--- a/tools/gn2bp/Android.bp.swp
+++ b/tools/gn2bp/Android.bp.swp
@@ -1979,8 +1979,8 @@
          "--header-path " +
          "$(genDir)/components/cronet/android/cronet_jni_registration.h " +
          "--manual_jni_registration " +
-         "--sources-exclusions " +
-         "[\"../../base/android/java/src/org/chromium/base/library_loader/LibraryLoader.java\", \"../../base/android/java/src/org/chromium/base/library_loader/LibraryPrefetcher.java\", \"../../base/android/java/src/org/chromium/base/process_launcher/ChildProcessService.java\", \"../../base/android/java/src/org/chromium/base/SysUtils.java\"]",
+         " " +
+         "",
     out: [
         "components/cronet/android/cronet_jni_registration.h",
         "components/cronet/android/cronet_jni_registration.srcjar",