Fix extend.t failure on VMS

The fileame that ultimately derives from __FILE__ is a full path
with a version on it, so allow those while still requiring the
important bits.

Author: craigberry

ext/XS-APItest/t/extend.t

@@ -75,6 +75,6 @@ SKIP:
       unless hwm_checks_enabled();
 
     ok(!eval { bad_EXTEND(); 1 }, "bad_EXTEND() should throw");
-    like($@, qr/^panic: XSUB XS::APItest::bad_EXTEND \(APItest\.c\) failed to extend arg stack/,
+    like($@, qr/(?i)^panic: XSUB XS::APItest::bad_EXTEND \(.*APItest\.c.*\) failed to extend arg stack/,
          "check panic message");
 }