fix looping memory test function

src/functions/MemoryTestFunction.cpp

@@ -84,6 +84,7 @@ bool memoryTestFunction::run() {
     const ssize_t ret = write(wfd, buffer, bufferSize);
     if (ret < 0) throw Error("Can't write to test file: %s\n", strerror(errno));
     bytesWritten += ret;
+  }
 
   const auto endWrite = std::chrono::high_resolution_clock::now();
 
@@ -93,7 +94,6 @@ bool memoryTestFunction::run() {
           (static_cast<double>(testFileSize) / (1024.0 * 1024.0)) /
               writeTime);
   LOGN(MTFUN, INFO) << "Sequential write test done!" << std::endl;
-  }
 
   if (!doNotReadTest) {
     auto *rawBuffer = new char[bufferSize + 4096];