Remove comment saying that we don't build debug rustc in CI, since we do

Author: tgnottingham

src/test/ui/rustc-rust-log.rs

@@ -1,9 +1,6 @@
 // run-pass
 // This test is just checking that we won't ICE if logging is turned
-// on; don't bother trying to compare that (copious) output. (Note
-// also that this test potentially silly, since we do not build+test
-// debug versions of rustc as part of our continuous integration
-// process...)
+// on; don't bother trying to compare that (copious) output.
 //
 // dont-check-compiler-stdout
 // dont-check-compiler-stderr