reproduction case for PR#30 fix

When the non-existent URI::javascript is loaded, $@ is left populated.  It is
cleared out the first time by loading URI::_foreign, but the second time
around nothing clears it.

MANIFEST

@@ -96,6 +96,7 @@ t/roytest4.html
 t/roytest5.html
 t/rsync.t
 t/rtsp.t
+t/scheme-exceptions.t
 t/sip.t
 t/sort-hash-query-form.t
 t/split.t

t/scheme-exceptions.t

@@ -0,0 +1,16 @@
+use strict;
+use warnings;
+
+use Test::More;
+use URI;
+
+plan skip_all => 'this test assumes that URI::javascript does not exist'
+    if eval 'require URI::javascript';
+plan tests => 4;
+
+for (0..1) {
+    my $uri = URI->new('javascript://foo/bar');
+
+    is($@, '', 'no exception when trying to load a scheme handler class');
+    ok($uri->isa('URI'), 'but URI still instantiated as foreign');
+}