Use hashFiles for Windows Cygwin package cache key
Upgrade actions/checkout and actions/upload-artifact in build sub-workflows
Add zx_string_to_utf8() unit tests and SZX IF1 chunk write/read tests
Update hacking/unittests.txt to reflect current test suite
Eliminate redundant attr lookup in display_write_if_dirty_timex()
Add comparison non-associativity deparse tests
Add scaler_for_size unit tests
Fix off-by-one in svg_startcapture allocation