Drop support for 32-bit x86 Android.

32-bit x86 Android is declining rapidly and it's possible that future Android NDK will drop this architecture (android/ndk#1772).

Also related issue: love2d/love#1889.

app/build.gradle

@@ -28,6 +28,12 @@ android {
             }
         }
 
+        ndk {
+            //noinspection ChromeOsAbiSupport
+            abiFilters 'armeabi-v7a', 'arm64-v8a', 'x86_64'
+            debugSymbolLevel 'full'
+        }
+
         def getAppName = {
             def nameArray = project.properties["app.name_byte_array"]
             def name = project.properties["app.name"]