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/duplicateClass/inTheSameModuleWithUsage.txt

@@ -26,10 +26,6 @@ package
 package p {
     public fun test(): kotlin.Unit
 
-    public final class A {
-        // -- Module: <m1> --
-    }
-
     public final class A {
         public constructor A()
         public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
@@ -37,8 +33,4 @@ package p {
         public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
         public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
     }
-
-    public final class B {
-        // -- Module: <m1> --
-    }
 }