Dump animation type with human readable string

With CL[1], WindowContainer will dump its SurfaceAnimator when
self animating, since mAnimationType is int, use valueToString to
dump AnimationType with human readable string for easy read and debug.

[1]: I8396e1fbce1960dc9dcd9de8c5cd47bfd18ba31a

Fix: 166435678
Test: build and dump with "adb dumpsys window" to check dumped
      mAnimationType

Change-Id: I56c355e381e85b095e0bdf7a6ca50097d4824275