Add //build/android/pylib/results/ to Android isolate packaging

This is needed before relanding
https://chromium-review.googlesource.com/c/chromium/tools/build/+/619228

TESTED=
I built tools_unittests and verified build/android/pylib/results/presentation/test_results_presentation.py
is listed in the .isolated file:
OUT=out/android-Release
TEST=tools_unittests
tools_webrtc/mb/mb.py isolate //$OUT $TEST
tools/swarming_client/isolate.py archive -I https://isolateserver.appspot.com -i $OUT/$TEST.isolate -s $OUT/$TEST.isolated

BUG=chromium:717417
NOTRY=True

Review-Url: https://codereview.webrtc.org/3006103002
Cr-Original-Commit-Position: refs/heads/master@{#19695}
Cr-Mirrored-From: https://chromium.googlesource.com/external/webrtc
Cr-Mirrored-Commit: f8ff0282c6b605f16fa5464b9496be1f6bac35ed

webrtc.gni

diff --git a/webrtc.gni b/webrtc.gni
index af4d6f9..7e74161 100644
--- a/webrtc.gni
+++ b/webrtc.gni
@@ -265,6 +265,7 @@
                            "*",
                            [
                              "configs",
+                             "data",
                              "public_configs",
                              "suppressed_configs",
                            ])
@@ -278,6 +279,14 @@
     if (!build_with_chromium && is_android) {
       android_manifest = webrtc_root + "test/android/AndroidManifest.xml"
       deps += [ webrtc_root + "test:native_test_java" ]
+
+      # Needed for build/android/pylib/results/presentation/test_results_presentation.py
+      data = [
+        "//build/android/pylib/results/",
+      ]
+      if (defined(invoker.data)) {
+        data += invoker.data
+      }
     }
   }
 }