Merge boxWithStdlib testData into box, delete BoxWithStdlib test

compiler/testData/codegen/box/dataClasses/equals/alreadyDeclaredWrongSignature.kt

@@ -0,0 +1,34 @@
+// WITH_RUNTIME
+
+data class B(val x: Int) {
+  fun equals(other: B): Boolean = false
+}
+
+data class C(val x: Int) {
+  fun equals(): Boolean = false
+}
+
+data class D(val x: Int) {
+  fun equals(other: Any?, another: String): Boolean = false
+}
+
+data class E(val x: Int) {
+  fun equals(x: E): Boolean = false
+  override fun equals(x: Any?): Boolean = false
+}
+
+fun box(): String {
+  B::class.java.getDeclaredMethod("equals", Any::class.java)
+  B::class.java.getDeclaredMethod("equals", B::class.java)
+
+  C::class.java.getDeclaredMethod("equals", Any::class.java)
+  C::class.java.getDeclaredMethod("equals")
+
+  D::class.java.getDeclaredMethod("equals", Any::class.java)
+  D::class.java.getDeclaredMethod("equals", Any::class.java, String::class.java)
+
+  E::class.java.getDeclaredMethod("equals", Any::class.java)
+  E::class.java.getDeclaredMethod("equals", E::class.java)
+
+  return "OK"
+}