Make the column number optional in the regex since not all platforms have column numbers.

Author: khuey

tests/ui/panics/location-detail-unwrap-multiline.rs

@@ -1,7 +1,7 @@
 //@ run-fail
 //@ compile-flags: -Cstrip=none -Cdebuginfo=line-tables-only -Copt-level=0
 //@ exec-env:RUST_BACKTRACE=1
-//@ regex-error-pattern: location-detail-unwrap-multiline\.rs:10:10\n
+//@ regex-error-pattern: location-detail-unwrap-multiline\.rs:10(:10)?\n
 //@ needs-unwind
 
 fn main() {