K2: Rework scopes for types with projection arguments for Out types

The only case when behavior is change is described at
 computeNonTrivialTypeArgumentForScopeSubstitutor

The idea is to avoid depending on the presence of @UnsafeVariance
and instead approximate captured types in covariant argument positions
before building substitution scopes

It's correct because for Captured(*) <: Supertype,
Out<Captured(*)> <: Out<Supertype> and when we've got @UnsafeVariance
value parameters at Out, it's ok to allow passing Supertype there.

^KT-57602 Fixed
^KT-54894 Fixed

compiler/testData/diagnostics/tests/scopes/variantProjections/dataClassCopy.fir.kt

@@ -0,0 +1,13 @@
+// ISSUE: KT-54764
+
+data class Out<out T>(val prop: T)
+
+fun foo(b: Out<*>) {
+    b.copy("") // error in K1, OK in K2
+}
+
+fun foo(a: Any) {
+    if (a is Out<*>) {
+        a.copy("")
+    }
+}