Merge branch 'tor-github/pr/1925'

changes/bug30992

src/core/or/circuit_st.h

src/core/or/circuitpadding.c

src/core/or/circuitpadding.h

src/test/test_circuitpadding.c

src/trunnel/circpad_negotiation.c

src/trunnel/circpad_negotiation.h

src/trunnel/circpad_negotiation.trunnel