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/qualifiedExpression/PackageVsClass.txt

@@ -56,18 +56,8 @@ public fun test(/*0*/ a_b: a.b): kotlin.Unit
 public fun test2(/*0*/ ab_c: a.b.c): kotlin.Unit
 
 package a {
-    public fun a_fun(): kotlin.Unit
-
-    public final class b {
-        // -- Module: <_m2> --
-    }
 
     package a.b {
-        public fun ab_fun(): kotlin.Unit
-
-        public final class c {
-            // -- Module: <_m1> --
-        }
     }
 }
 
@@ -121,16 +111,7 @@ public fun test(/*0*/ a_b: a.b): kotlin.Unit
 public fun test2(/*0*/ ab_c: a.b.c): kotlin.Unit
 
 package a {
-    public fun a_fun(): kotlin.Unit
-
-    public final class b {
-        // -- Module: <m2> --
-    }
 
     package a.b {
-
-        public final class c {
-            // -- Module: <m1> --
-        }
     }
 }