If the tarantool repository is used as a submodule named <foobar> in
another repository, then the statically built binary will be placed in

  <binary_dir>/<foobar>/src/tarantool

not in

  <binary_dir>/src/tarantool

where static-build/CMakeLists.txt currently tries to look it up in order
to run `ctest` and so we can't use static-build/CMakeLists.txt as is.

Let's instead use

  <install_dir>/bin/tarantool

This way `ctest` will work for static-build in both open-source and EE
repository without requiring any modifications.