Enable the structured optimization log and specify where it is printed.
The accepted values are:
  Directory - Format the structured optimization log as JSON and print it to files in a directory.
              The directory is specified by OptimizationLogPath. If OptimizationLogPath is not set,
              the target directory is DumpPath/optimization_log.
     Stdout - Print the structured optimization log to the standard output.
       Dump - Dump optimization trees for IdealGraphVisualizer according to the PrintGraph option.
It is possible to specify multiple comma-separated values.
