Fix logDone message for TestCopySingleFileToExistDir

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Add Build prefix to Copy tests

Now we can do "-run TestBuild" to test all build-tests and "-run
TestBuildCopy" for test all copy-tests

Signed-off-by: Alexandr Morozov <lk4d4@docker.com>
Merge pull request #8105 from LK4D4/build_test_little_fix

Little fixes in cli build tests