Modify sanitize_json.d to support new runtime directory object_

[JinShil]

Required for dlang/druntime#2399 to pass the test suite.

[dlang-bot]

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[wilzbach]

Can we please not merge stuff with only a 1 hour waiting period?

In this case, moving things into core should be the way to go instead of creating a new top-level package...

[wilzbach]

Revert: #9052