Add regression tests to cover Unused symbol with private anonymous object property

^KT-39454 Fixed

idea/testData/inspectionsLocal/unusedSymbol/privateProperty.kt

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+// PROBLEM: Property "bar" is never used
+
+class Foo {
+    private val foo = object {
+        var bar<caret>: Int = 42
+    }
+}

idea/testData/inspectionsLocal/unusedSymbol/privateProperty.kt.after

@@ -0,0 +1,8 @@
+// WITH_RUNTIME
+// PROBLEM: Property "bar" is never used
+
+class Foo {
+    private val foo = object {
+        var bar: Int = 42
+    }
+}

idea/testData/inspectionsLocal/unusedSymbol/privatePropertyViaGetter.kt

@@ -0,0 +1,13 @@
+// WITH_RUNTIME
+// PROBLEM: none
+
+class Foo {
+    private val foo = object {
+        var bar<caret>: Int = 42
+    }
+
+    fun baz(): Int {
+        val z = foo.bar
+        return z
+    }
+}

idea/testData/inspectionsLocal/unusedSymbol/privatePropertyViaSetter.kt

@@ -0,0 +1,12 @@
+// WITH_RUNTIME
+// PROBLEM: none
+
+class Foo {
+    private val foo = object {
+        var bar<caret>: Int = 42
+    }
+
+    fun baz(value: Int) {
+        foo.bar = value
+    }
+}