[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/ir/irText/classes/enumClassModality.kt

@@ -1,6 +1,3 @@
-// KT-64271, KT-64382
-// IGNORE_BACKEND_K2: NATIVE, WASM, JS_IR, JS_IR_ES6
-
 enum class TestFinalEnum1 {
     X1
 }