Fix CTS tests for LayerDrawable, ScaleDrawable, InsetDrawable

LayerDrawable's bounds should never change when the state or level
changes, but the child bounds may change. The CTS test was checking
internal implementation details rather than API compatibility.

ScaleDrawable only needs to check child opacity when the level is
greater than 0, otherwise the child isn't going to draw and it's
always TRANSPARENT.

InsetDrawable only needs to update layer bounds when the contained
drawable changes, or when the inset changes. Additionally, calling
inflate() multiple times on the same drawable has undefined behavior
and we shouldn't be testing that.

Also updates calls to deprecated Resources.getDrawable().

Bug: 19863229
Bug: 19863468
Bug: 19863765
Change-Id: If37c0ec25969cce765d6d3a9ca0d1f141f3580e6