FIR: Do not build synthetic property named with first capital character

compiler/testData/codegen/box/syntheticExtensions/firstCapitalizedProperty.kt

@@ -0,0 +1,29 @@
+// TARGET_BACKEND: JVM
+
+// MODULE: lib
+
+// FILE: test/UI.java
+package test;
+public class UI {
+    public static String foo() {
+        return "OK";
+    }
+}
+
+// FILE: Parent.java
+public class Parent {
+    public String getUI() { return "fail"; }
+}
+
+// MODULE: main(lib)
+// FILE: main.kt
+
+import test.UI;
+
+class Derived : Parent() {
+    fun bar(): String = UI.foo()
+}
+
+fun box(): String {
+    return Derived().bar()
+}