Auto merge of #14446 - heycam:should-traverse, r=bholley
Auto merge of #14446 - heycam:should-traverse, r=bholley

stylo: Add FFI function to check if a node is dirty.

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This is the Servo-side change from https://bugzilla.mozilla.org/show_bug.cgi?id=1321284, which has already been reviewed by bholley.

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