Tests: Avoid unnecessary copy of cmake in RunCMake.separate_arguments
The cmake
binary can be quite large in debug builds.
Original Description
The "cmake" binary in a debug build can be quite large, around 274MB in my case. Try using a hardlink first when building the test directory for the "separate_arguments" testcases and only fall back to copying if that is not supported. This save half a gigabyte of space and disk I/O.
Topic-rename: test-separate_arguments
Edited by Brad King