Do not render declarations from other modules in diagnostic tests

Because PackageViewDescriptor may consist of several package fragments from
different modules (see LazyPackageViewDescriptorImpl#fragments), we now filter
out fragments from irrelevant modules before rendering them into the .txt

compiler/testData/diagnostics/tests/multimodule/duplicateSuper/sameSuperTrait.txt

@@ -52,20 +52,4 @@ public final class Foo : p.A, p.B {
 }
 
 package p {
-
-    public interface A : p.Base {
-        // -- Module: <m1> --
-    }
-
-    public interface B : p.Base {
-        // -- Module: <m2> --
-    }
-
-    public interface Base {
-        // -- Module: <m1> --
-    }
-
-    public interface Base {
-        // -- Module: <m2> --
-    }
 }