Revert bump to API 26 and fix Android tests failures

Summary:
This reverts a3931e9531

The open source `test_android` job is not configured to use Android 26 quite yet. I've spent a couple of days trying to get our Android tests back in working order, with no luck.

I'm reverting the change that bumped React Native to use build tools 26 + Android SDK 26. I encourage contributors interested in making this change happen to work on getting our Android tests working with API 26.

This will allow us to focus on getting `test_android` back to green, and _then_ we can work on bumping to API 26 while keeping tests green.

Reviewed By: fkgozali

Differential Revision: D8066226

fbshipit-source-id: 9bfd58a7f081c0971b78b331073e70545c21ca6d

local-cli/templates/HelloWorld/android/app/build.gradle

@@ -94,8 +94,8 @@ def enableSeparateBuildPerCPUArchitecture = false
 def enableProguardInReleaseBuilds = false
 
 android {
-    compileSdkVersion 26
-    buildToolsVersion "26.0.3"
+    compileSdkVersion 23
+    buildToolsVersion "23.0.1"
 
     defaultConfig {
         applicationId "com.helloworld"
@@ -138,7 +138,7 @@ android {
 
 dependencies {
     compile fileTree(dir: "libs", include: ["*.jar"])
-    compile "com.android.support:appcompat-v7:26.0.2"
+    compile "com.android.support:appcompat-v7:23.0.1"
     compile "com.facebook.react:react-native:+"  // From node_modules
 }
 

local-cli/templates/HelloWorld/android/build.gradle

@@ -3,10 +3,6 @@
 buildscript {
     repositories {
         jcenter()
-        maven {
-            url 'https://maven.google.com/'
-            name 'Google'
-        }
     }
     dependencies {
         classpath 'com.android.tools.build:gradle:2.2.3'
@@ -20,10 +16,6 @@ allprojects {
     repositories {
         mavenLocal()
         jcenter()
-        maven {
-            url 'https://maven.google.com/'
-            name 'Google'
-        }
         maven {
             // All of React Native (JS, Obj-C sources, Android binaries) is installed from npm
             url "$rootDir/../node_modules/react-native/android"