K2: Fix false-negative RETURN_TYPE_MISMATCH

^KT-53987 Fixed
^KT-55932 Fixed

compiler/testData/diagnostics/tests/delegatedProperty/provideDelegate/noOperatorModifierOnProvideDelegate.fir.kt

@@ -0,0 +1,16 @@
+// !DIAGNOSTICS: -UNUSED_PARAMETER
+
+import kotlin.reflect.KProperty
+
+class StringDelegate(val s: String) {
+    operator fun getValue(a: Any?, p: KProperty<*>): Int = 42
+}
+
+// NB no operator
+fun String.provideDelegate(a: Any?, p: KProperty<*>) = StringDelegate(this)
+
+operator fun String.getValue(a: Any?, p: KProperty<*>) = this
+
+val test1: String by "OK"
+val test2: Int by <!DELEGATE_SPECIAL_FUNCTION_RETURN_TYPE_MISMATCH!>"OK"<!>
+val test3 by "OK"

compiler/testData/diagnostics/tests/delegatedProperty/provideDelegate/noOperatorModifierOnProvideDelegate.kt

@@ -1,4 +1,3 @@
-// FIR_IDENTICAL
 // !DIAGNOSTICS: -UNUSED_PARAMETER
 
 import kotlin.reflect.KProperty