Atest: validate every Java method before testing.

Bug: 177970662

Test: m atest
atest-dev --dry-run -cv \
 ChooserActivityTest#twoVisibleImagePreview,threeVisibleImagePreview
 # will fail because "threeVisibleImagePreview" does not exist.

atest-dev --dry-run -cv \
 ChooserActivityTest#twoVisibleImagePreview,visiblePreviewTitleWithInvalidThumbnail
 # will move on because they are all valid methods.

Change-Id: I48dc83e48ba3199e5ccccbbe9ecca7ff7c122f47
2 files changed