Merge branch 'heap_lang_lib' into 'master'

Add some trivial but useful heaplang libraries.

See merge request !291
6 jobs for master in 14 minutes and 21 seconds (queued for 1 second)
Status Job ID Name Coverage
  Build
passed #38973
fp
build-coq.8.10.dev

00:12:52

passed #38977
fp
build-coq.8.7.2

00:05:51

passed #38976
fp
build-coq.8.8.2

00:06:33

passed #38975
fp-timing
build-coq.8.9.0

00:05:57

passed #38974
fp
build-coq.8.9.1

00:07:07

passed #38972
fp
build-coq.dev

00:14:21