FIR: add getter visibility and setter return type checks

compiler/testData/diagnostics/tests/AbstractAccessor.fir.kt

@@ -4,14 +4,14 @@ abstract class My {
         <!PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY!>private<!> set
 
     abstract val y: Int
-        protected get
+        <!GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY!>protected<!> get
 
     abstract protected var z: Int
-        internal get
+        <!GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY!>internal<!> get
         <!PRIVATE_SETTER_FOR_ABSTRACT_PROPERTY!>private<!> set
 
     abstract internal val w: Int
-        protected get
+        <!GETTER_VISIBILITY_DIFFERS_FROM_PROPERTY_VISIBILITY!>protected<!> get
 
     abstract var u: Int
         protected set

compiler/testData/diagnostics/tests/backingField/SetterWithExplicitType.fir.kt

@@ -1,26 +0,0 @@
-// KT-7042 Providing return type for property setter is not reported as error
-
-var x: Int = 1
-
-// No backing field!
-var y: Int
-    get() = x
-    set(value): Any {
-        x = value
-    }
-
-var z: Int
-    get() = x
-    set(value): Unit {
-        x = value
-    }
-
-var u: String = ""
-    set(value): Unit {
-        field = value
-    }
-
-var v: String = ""
-    set(value): String {
-        field = value
-    }

compiler/testData/diagnostics/tests/backingField/SetterWithExplicitType.kt

@@ -1,3 +1,4 @@
+// FIR_IDENTICAL
 // KT-7042 Providing return type for property setter is not reported as error
 
 var x: Int = 1