fix Poolable object leak context issue

[lbtrace]

PR Description

• As we know ObjectPool cache some Poolable Objects, but some Poolable Object reference to View Object, and View Object reference to Context Object, And ObjectPool is static, so leak Context. For exsmple, ObjectPool.objects ---> AnimatedMoveViewJob.view ---> View.mContext ---> Context

• For this issue, I Clear Poolable Object fields when Poolable Object is recycled. Please check patch code

• I think lots of memory leak occurs when using MPAndroidChart, so please merge this patch.

[S0und]

I would really appreciate this patch. Leakcanary caught the memory leak for me.

[NunoPontes]

Do you have a schedulle on when this will be in a new version?

[SubhrajyotiSen]

Merged this at https://github.com/SubhrajyotiSen/MPAndroidChart which will be an updated fork

[johnsabilla]

Hello, Leak Canary also detected this memory leak in our app. Any chance this PR will be merged soon?

[hannesa2]

It's included here https://github.com/AppDevNext/AndroidChart/releases/tag/3.1.0.25