I am not aware of any technical term for such adjectives. Like you, I will be waiting for an answer. In the meantime, note that the underlying sentence (the 'kernel' sentence) is *to break the brick is hard It is obligatory to replace the subject 'to break the brick' with the dummy subject 'it' and move the subject to the apparent position of adjective complement.
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CalifJim *to break the brick is hardHi, CJ,
It is obligatory to replace the subject 'to break the brick' with the dummy subject 'it' and move the subject to the apparent position of adjective complement.