This required the following changes:
- Delayloading ICU in all of our tests, and skipping tests where it
could not be loaded
- Adding a new test group which skips the PolicyTests, which cannot be
run on some editions which have no app platform.
In addition, instead of onboarding new failing test passes, this pull
request finally repairs the broken ConPTY tests (which diverged from the
OSS implementation and had to be re-en-verged)
Closes MSFT-61409507
Reflected from OS PR !15022958
987fce20a1