[FIR] Don't create backing field for property without explicit type

#KT-41977 Fixed

compiler/fir/analysis-tests/testData/resolve/properties/noBackingFieldInProperty.kt

@@ -0,0 +1,15 @@
+// ISSUE: KT-41977
+
+class A {
+    val field: String = "" // (1)
+
+    val x
+        get() = field.length // should be ok, resolve to (1)
+}
+
+class B {
+    val field: String = ""
+
+    val x: Int
+        get() = field.<!UNRESOLVED_REFERENCE!>length<!> // should be an error
+}

compiler/fir/analysis-tests/testData/resolve/properties/noBackingFieldInProperty.txt

@@ -0,0 +1,29 @@
+FILE: noBackingFieldInProperty.kt
+    public final class A : R|kotlin/Any| {
+        public constructor(): R|A| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final val field: R|kotlin/String| = String()
+            public get(): R|kotlin/String|
+
+        public final val x: R|kotlin/Int|
+            public get(): R|kotlin/Int| {
+                ^ this@R|/A|.R|/A.field|.R|kotlin/String.length|
+            }
+
+    }
+    public final class B : R|kotlin/Any| {
+        public constructor(): R|B| {
+            super<R|kotlin/Any|>()
+        }
+
+        public final val field: R|kotlin/String| = String()
+            public get(): R|kotlin/String|
+
+        public final val x: R|kotlin/Int|
+            public get(): R|kotlin/Int| {
+                ^ this@R|/B|.F|/B.x|.<Unresolved name: length>#
+            }
+
+    }