This updates a number of ignore-test tests, and removes a few completely
outdated tests due to the feature being tested no longer being supported.
This brings a number of bench/shootout tests up to date so they're compiling
again. I make no claims to the performance of these benchmarks, it's just nice
to not have bitrotted code.
Closes#2604Closes#9407
Fixes#1896 which was never truly fixed, just masked.
The given tests would have failed had they used `~fn()` and
not `@fn()`. They now result in compilation errors.
Fixes#2978.
Necessary first step for #2202, #2263.
