[test] rearrange test files so they're not in the fixtures folder

test/storage/storage.cpp

@@ -1,12 +1,9 @@
 #include "storage.hpp"
 
-#include <mbgl/platform/platform.hpp>
-
 std::unique_ptr<mbgl::test::Server> Storage::server;
 
 void Storage::SetUpTestCase() {
-    const auto program = mbgl::platform::applicationRoot() + "/TEST_DATA/storage/server.js";
-    server = std::make_unique<mbgl::test::Server>(program.c_str());
+    server = std::make_unique<mbgl::test::Server>("test/storage/server.js");
 }
 
 void Storage::TearDownTestCase() {