Tests: minor, move diagnostic test missingNames.kt

Looks like it was placed in the `duplicateJvmSignature` directory by
mistake.

compiler/testData/diagnostics/tests/incompleteCode/missingNames.fir.kt

@@ -0,0 +1,68 @@
+// !DIAGNOSTICS: -DUPLICATE_CLASS_NAMES
+<!FUNCTION_DECLARATION_WITH_NO_NAME!>fun ()<!> {
+
+}
+
+<!FUNCTION_DECLARATION_WITH_NO_NAME!>fun Outer.()<!> {
+
+}
+
+val<!SYNTAX!><!> : Int = 1
+
+class<!SYNTAX!><!> {
+
+}
+
+object<!SYNTAX!><!> {
+
+}
+
+interface<!SYNTAX!><!> {
+
+}
+
+enum class<!SYNTAX!><!> {
+
+}
+
+annotation class<!SYNTAX!><!> {
+
+}
+
+class Outer {
+    <!FUNCTION_DECLARATION_WITH_NO_NAME!>fun ()<!> {
+
+    }
+
+    val<!SYNTAX!><!> : Int = 1
+
+    class<!SYNTAX!><!> {
+
+    }
+
+    object<!SYNTAX!><!> {
+
+    }
+
+    interface<!SYNTAX!><!> {
+
+    }
+
+    enum class<!SYNTAX!><!> {
+
+    }
+
+    annotation class<!SYNTAX!><!> {
+
+    }
+}
+
+fun outerFun() {
+    fun () {
+
+    }
+    fun () {
+
+    }
+}
+