K2: Propagate explicit getter type to the property without initializer

In K1, we have the rules like:
- if there's explicit type of a property, then use it
- if there's an initializer, obtain its expression-type
- Otherwise, use getter's return type

The case when getter's type is implicit is handled at
FirDeclarationsResolveTransformer.transformProperty

^KT-56707 Fixed

compiler/testData/diagnostics/tests/properties/inferPropertyTypeFromGetter.kt

@@ -0,0 +1,19 @@
+// FIR_IDENTICAL
+// ISSUE: KT-56707
+
+class Foo0 {
+    val child = 1
+    val allChildren
+        get(): Int = child + allChildren // Should not be TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM on `allChildren` reference
+}
+
+class Foo1 {
+    val child = 1
+    val allChildren
+        get() = child + 1
+}
+
+fun use() {
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int")!>Foo0().allChildren<!>
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.Int")!>Foo1().allChildren<!>
+}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/explicitGetterType.fir.kt

@@ -1,18 +0,0 @@
-// !CHECK_TYPE
-val x get(): String = foo()
-val y get(): List<Int> = bar()
-val z get(): List<Int> {
-    return bar()
-}
-
-val u get(): String = <!UNRESOLVED_REFERENCE!>field<!>
-
-fun <E> foo(): E = null!!
-fun <E> bar(): List<E> = null!!
-
-
-fun baz() {
-    x checkType { _<String>() }
-    y checkType { _<List<Int>>() }
-    z checkType { _<List<Int>>() }
-}

compiler/testData/diagnostics/tests/properties/inferenceFromGetters/explicitGetterType.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // !CHECK_TYPE
 val x get(): String = foo()
 val y get(): List<Int> = bar()

compiler/testData/diagnostics/tests/properties/kt56707.kt

@@ -0,0 +1,13 @@
+// FIR_IDENTICAL
+// WITH_STDLIB
+// ISSUE: KT-56707
+
+class Foo {
+    val children = mutableSetOf<Foo>()
+    val allChildren
+        get() : Set<Foo> = (children + children.flatMap { it.allChildren }).toSet() // Should not be TYPECHECKER_HAS_RUN_INTO_RECURSIVE_PROBLEM on `allChildren` reference
+}
+
+fun use() {
+    <!DEBUG_INFO_EXPRESSION_TYPE("kotlin.collections.Set<Foo>")!>Foo().allChildren<!>
+}