[FIR] Call distinctBy for containsMultipleNonSubsumed

Otherwise, when analyzing
`PsiTypeParameterListOwner` in the
related test, we (after flattening and
`nonSubsumed()`) get 2 `JvmMember.accept`
from the same very java enhancement
scope `JvmMember`.

^KT-65972

compiler/testData/diagnostics/tests/intersectionWithMultipleDefaultsInJavaWithAdditionalSymbolsAfterNonSubsumed.fir.kt

@@ -1,29 +0,0 @@
-// FILE: JvmElement.java
-public interface JvmElement {
-    default void accept() {}
-}
-
-// FILE: JvmMember.java
-public interface JvmMember extends JvmElement {
-    default void accept() {}
-}
-
-// FILE: PsiJvmMember.java
-// Provides a phantom IO
-public interface PsiJvmMember extends JvmMember, JvmElement {}
-
-// FILE: PsiTypeParameterListOwner.java
-// Must also provide a phantom IO
-public interface PsiTypeParameterListOwner extends PsiJvmMember, JvmMember {}
-
-// FILE: JvmClass.java
-public interface JvmClass extends JvmMember, JvmElement {
-    default void accept() {}
-}
-
-// FILE: PsiClass.java
-public interface PsiClass extends PsiTypeParameterListOwner, JvmClass {}
-
-// FILE: Main.kt
-
-<!CANNOT_INFER_VISIBILITY!>class K<!> : PsiClass

compiler/testData/diagnostics/tests/intersectionWithMultipleDefaultsInJavaWithAdditionalSymbolsAfterNonSubsumed.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // FILE: JvmElement.java
 public interface JvmElement {
     default void accept() {}