This patch modifies the invocation of CMake's add_custom_command()
function so that instead of specifying all 462 output files
explicitly, it instead specifies a single file,
builtin_uniform_tests.list, which receives a list of all the files
generated.

It is safe not to specify the individual output files since there are
no other build steps that depend on them, so there is no danger of the
build step happening at the wrong time.

This prevents CMake from trying to output an outrageously long
diagnostic message listing all the files generated by the custom
command, a message that was too long to work with the NMake back-end
used on Windows.

Bugzilla:https://bugs.freedesktop.org/show_bug.cgi?id=39873