[CMake] CTest location of executables on Windows

[Clifford Yapp]

We have a ctest setup in our software that runs a series of test
executables , and the setup works well on Linux.  When trying to run
the same setup on Windows, ctest reports the following:

Test project C:/Users/User/project-build
              Start   1: bu_test_1
Could not find executable tester_bu_test_1
Looked in the following places:
tester_bu_test_1
tester_bu_test_1.exe
Debug/tester_bu_test_1
Debug/tester_bu_test_1.exe
Release/tester_bu_test_1
Release/tester_bu_test_1.exe
Unable to find executable: tester_bu_test_1

The executable is actually located at Debug/bin/tester_bu_test_1.exe
(all of our binaries are put in that subdirectory) but I can't figure
out how to let CTest know to search there.  Does anyone know how to
specify search directories for CTest to look in?

Thanks,
CY