The commit "Clean up CMake build tree 'bin' directory" changed the
setting of EXECUTABLE_OUTPUT_PATH that affects the cmcurl directory to
empty. We now fix the 'curl' test to refer to the LIBCURL executable
locally. When CMAKE_BUILD_CURL_SHARED is enabled we now put cmcurl.dll
next to the cmake executable.
These changes remove use of EXECUTABLE_OUTPUT_PATH from cmcurl.