Surface.java: decrease native allocation size

The original change caused a new camera test flake. The camera app has a
bug where it doesn't release surfaces, and this caused the GC to churn
and captures to time out. This led to a rollback of this flag.

Lowering the value to hopefully cause less churn but still put enough
pressure on the GC to actually GC these objects.

Tested with:
  - atest "CtsCameraTestCases:android.hardware.camera2.cts.CameraExtensionSessionTest#testRepeatingAndCaptureCombined[1]" --iteration 3
  - atest "android.view.cts.SurfaceOOMTest#testSurfaceGarbageCollection" --iterations 3

Bug: 306193257
Bug: 324071855
Test: atest, see above
Change-Id: I405b388286939df015e8934b76f8cd1781228f5a