meson: use is_cross_build() where possible

meson: use is_cross_build() where possible

In previous commit the first use of meson.can_run_host_binaries() was
introduced. This is a guard around compiler.run() to ensure it's
actually possible to execute the provided.

In other places we've been having the same issue, but here `not
meson.is_cross_build()` is used as guard. This does the trick, but it
also prevents the code from running even when an exe_wrapper is
configured.

Switch to using meson.can_run_host_binaries() here as well.

There is another place left that still uses `not
meson.is_cross_build()`, but here it's a guard around fs.exists(). That
function will always run on the build machine, so checking for
cross-compilation is still in place here.

Signed-off-by: Toon Claes <toon@iotcl.com>
Acked-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>