[NI] Fix detecting expected type variable for postponed atoms

#KT-36819 Fixed

compiler/testData/diagnostics/tests/inference/kt36819.fir.kt

@@ -0,0 +1,18 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE
+// ISSUE: KT-36819
+
+fun <K> select(vararg x: K) = x[0]
+interface A
+class B: A
+class C: A
+fun <T> id1(x: T): T = x
+fun <R> id2(x: R): R = x
+
+class Out<out R>(x: R)
+
+fun main() {
+    val x1 = select(id1 { B() }, id2 { C() })
+    val x2 = select({ B() }, { C() }) // OK, CST = () -> A
+    val x3 = select(id1(Out(B())), id2(Out(C()))) // OK, CST = Out<A>
+}

compiler/testData/diagnostics/tests/inference/kt36819.kt

@@ -0,0 +1,18 @@
+// !LANGUAGE: +NewInference
+// !DIAGNOSTICS: -UNUSED_PARAMETER -UNUSED_VARIABLE
+// ISSUE: KT-36819
+
+fun <K> select(vararg x: K) = x[0]
+interface A
+class B: A
+class C: A
+fun <T> id1(x: T): T = x
+fun <R> id2(x: R): R = x
+
+class Out<out R>(x: R)
+
+fun main() {
+    val x1 = select(id1 { B() }, id2 { <!TYPE_MISMATCH, TYPE_MISMATCH!>C()<!> })
+    val x2 = select({ B() }, { C() }) // OK, CST = () -> A
+    val x3 = select(id1(Out(B())), id2(Out(C()))) // OK, CST = Out<A>
+}

compiler/testData/diagnostics/tests/inference/kt36819.txt

@@ -0,0 +1,33 @@
+package
+
+public fun </*0*/ T> id1(/*0*/ x: T): T
+public fun </*0*/ R> id2(/*0*/ x: R): R
+public fun main(): kotlin.Unit
+public fun </*0*/ K> select(/*0*/ vararg x: K /*kotlin.Array<out K>*/): K
+
+public interface A {
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class B : A {
+    public constructor B()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class C : A {
+    public constructor C()
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}
+
+public final class Out</*0*/ out R> {
+    public constructor Out</*0*/ out R>(/*0*/ x: R)
+    public open override /*1*/ /*fake_override*/ fun equals(/*0*/ other: kotlin.Any?): kotlin.Boolean
+    public open override /*1*/ /*fake_override*/ fun hashCode(): kotlin.Int
+    public open override /*1*/ /*fake_override*/ fun toString(): kotlin.String
+}