104f7de5934f13b837fcf21f6d6b2559799eabe2 remove old bootstrap relevant code (tryphe)
Pull request description:
This picks up #15954
I fixed the code and added at a functional test utilizing the scripts in `contrib/linearize` as suggested by @MarcoFalke .
ACKs for top commit:
laanwj:
ACK 104f7de5934f13b837fcf21f6d6b2559799eabe2
Tree-SHA512: acac9f285f9785fcbc3afc78118461e45bec2962f90ab90e9f82f3ad28adc90a44f0443b712458ccf486e46d891eb8a67f53e7bee5fa6d89e4387814fe03f117