Merge boxWithStdlib testData into box, delete BoxWithStdlib test

compiler/testData/codegen/box/reflection/genericSignature/kt5112.kt

@@ -0,0 +1,28 @@
+// WITH_REFLECT
+
+package test
+
+class G<T>(val s: T) {
+
+}
+
+public interface ErrorsJvmTrait {
+    companion object {
+        public val param : G<String> = G("STRING")
+    }
+}
+
+public class ErrorsJvmClass {
+    companion object {
+        @JvmField public val param : G<String> = G("STRING")
+    }
+}
+
+fun box(): String {
+    val genericTypeInClassObject = ErrorsJvmTrait.javaClass.getDeclaredField("param").getGenericType()
+    if (genericTypeInClassObject.toString() != "test.G<java.lang.String>") return "fail1: $genericTypeInClassObject"
+
+    val genericTypeInClass = ErrorsJvmClass::class.java.getField("param").getGenericType()
+    if (genericTypeInClass.toString() != "test.G<java.lang.String>") return "fail1: genericTypeInClass"
+    return "OK"
+}