Rename test in TEST_MAPPING

ToastTest became ToastWindowTest in ag/10919524, updating TEST_MAPPING
to reflect that.

Test: croot frameworks/base/core/java/android/app && atest --dry-run --test-mapping
Test: croot frameworks/base/core/java/android/widget && atest --dry-run --test-mapping
Test: croot frameworks/base/services/core/java/com/android/server && atest --dry-run --test-mapping
Bug: 152973950
Change-Id: I5b9e9b83d17c4a93a1e830c26d7f44001ccf175d
3 files changed