Don't test line numbers on *Package classes

Package classes in line number tests only contain "1" as the first line number
of a single function, so there's no point in testing it. The test was failing
due to the latest changes in the order of generation of classfiles (first $src,
then facade)

compiler/testData/lineNumber/custom/tryCatchFinally.kt

@@ -16,4 +16,4 @@ fun foo() {
     }
 }
 
-// 1 2 3 7 5 7 10 11 15 13 15 10
+// 2 3 7 5 7 10 11 15 13 15 10