Fix bug #4231.
Make --fverbose-asm a bit less verbose.
Fix bug #4229.
Fix some missing conditions on peephole optimizer rules.
Remove some sm83 peephole optimizer rules, for which no tests were found; towards fixing bug #4171.
Disable part of a test for pdk15, to make the test fit into pdk15 code memory.
Fixes for signed _BitInt(1).
Disable test for low-memory pdk via MakeList rather than #ifdef.