Restore saveLayer APIs back into the public API.

The saveLayer APIs are restored from @removed but will treat input
as ALL_SAVE_FLAGS and generate exceptions on newer API levels.

We internally used these calls in one situation that now use a
different @hide API to support the previous behavior until we
refactor that code.

Partial revert of "Remove deprecated android.graphics.Canvas APIs"
This reverts commit 7b837616.

Bug: 77276963
Bug: 73777445
Test: CtsGraphicsTestCases
Change-Id: I7acd4ffd5ac41a58d2be8b48cf50119c2b896708