gn2bp: add javacflag to skip GEN_JNI stub generation

This conflicts as the fully-featured GEN_JNI is already generated by
another genrule.

Test: none
Change-Id: I522501444b02d2a304e81d86d86b0c8f3589035c
diff --git a/tools/gn2bp/Android.bp.swp b/tools/gn2bp/Android.bp.swp
index 3d32f0a..84eab9b 100644
--- a/tools/gn2bp/Android.bp.swp
+++ b/tools/gn2bp/Android.bp.swp
@@ -4760,6 +4760,9 @@
         "cronet_aml_java_jni_annotation_preprocessor",
     ],
     sdk_version: "module_current",
+    javacflags: [
+        "-Aorg.chromium.chrome.skipGenJni",
+    ],
 }
 
 // GN: //base/android/jni_generator:jni_processor