[FIR] Don't remove subsumed members from intersection overrides's overriddens

This fixes a bunch of missing overridden symbols in IR.
This is also required for fixing KT-59921 in the following commit
where we need to keep all overridden symbols of intersection overrides
so that we can enhance them properly.

#KT-57300 Fixed
#KT-57299 Fixed
#KT-59921
#KT-57300
#KT-62788
#KT-64271
#KT-64382

compiler/testData/diagnostics/tests/override/intersectionWithSubsumedWithSubstitution.kt

@@ -0,0 +1,18 @@
+// FIR_IDENTICAL
+
+class KtFirPsiJavaClassSymbol : KtFirNamedClassOrObjectSymbolBase(), KtFirPsiSymbol<String, String>
+open class KtFirNamedClassOrObjectSymbolBase : KtNamedClassOrObjectSymbol(), KtFirSymbol<String>
+abstract class KtNamedClassOrObjectSymbol : KtLifetimeOwner
+
+interface KtFirPsiSymbol<P, S> : KtFirSymbol<S>
+
+interface KtLifetimeOwner {
+    val token: String
+}
+
+interface KtSymbol : KtLifetimeOwner
+
+interface KtFirSymbol<out S> : KtSymbol, KtLifetimeOwner {
+    override val token: String get() = ""
+}
+