Delete SupportAndroidLibraryPlugin

Move the last bits of functionality to AndroidXPlugin.
Delete SupportAndroidLibraryPlugin.
We are down to a single plugin!!!

Test: ./gradelw assembleDebug
Change-Id: I76eb5e09b393424410bd612aab79c317f0473025
diff --git a/benchmark/build.gradle b/benchmark/build.gradle
index fb56c60..49db68b 100644
--- a/benchmark/build.gradle
+++ b/benchmark/build.gradle
@@ -19,7 +19,8 @@
 import androidx.build.LibraryVersions
 
 plugins {
-    id("SupportAndroidLibraryPlugin")
+    id("AndroidXPlugin")
+    id("com.android.library")
     id("kotlin-android")
 }