tests: fix the flaky test test-logtoprocess.t
The main change is that we're waiting for the [touched] file to appear for 5 seconds instead of 0.1 seconds. Also, instead of implementing wait-on-file from scratch, we use the existing one from testlib/ that works well.
fn main() {
cc::Build::new()
.warnings(true)
.file("src/sendfds.c")
.file("src/sighandlers.c")
.compile("procutil");
}