Output PASSED 1 tests in semver test

Testing on Android (in ci/runtest-android.rs) seems to depend on the
test outputting it was successful.

Author: Thomasdezeeuw

libc-test/test/semver.rs

@@ -8,4 +8,5 @@ include!(concat!(env!("OUT_DIR"), "/semver.rs"));
 
 fn main() {
     // The test is about the imports created in `semver.rs`.
+    println!("PASSED 1 tests");
 }