Add compile-fail tests for malformed glob imports

Author: brson

src/test/compile-fail/import-glob-path.rs

@@ -0,0 +1,2 @@
+// error-pattern:cannot path into a glob
+import foo::*::bar

src/test/compile-fail/import-glob-rename.rs

@@ -0,0 +1,10 @@
+// error-pattern:globbed imports can't be renamed
+
+import baz = foo::*;
+
+mod foo {
+    fn bar() {}
+}
+
+fn main() {
+}