Copy format.sh and CONFIG.stress to the test/format build directory with CMake

Reproducing the issue:

# Build using CMake

mkdir my_build

cd my_build

cmake -G Ninja ../.

ninja

# Execute format.sh

cd ../test/format

./format.sh

format.sh: format program "./t" not found

If you copy the binary t to the current directory, the following issue occurs:

format.sh: wt program "../../wt" not found 

Would be great to check if other scripts expect paths that may not work when building with CMake.

Definition of Done:

Be able to run test/format after building with CMake.