adb: switch tests to python3.

Test: treehugger
Change-Id: Ia1f6a659e23f5d9e63c9b106c60d56b5b954b19c
diff --git a/adb/Android.bp b/adb/Android.bp
index 5073568..675525c 100644
--- a/adb/Android.bp
+++ b/adb/Android.bp
@@ -696,10 +696,10 @@
     test_suites: ["general-tests"],
     version: {
         py2: {
-            enabled: true,
+            enabled: false,
         },
         py3: {
-            enabled: false,
+            enabled: true,
         },
     },
 }