Most of this migration was performed automatically with `zig fmt`. There
were a few exceptions which I had to manually fix:
* `@alignCast` and `@addrSpaceCast` cannot be automatically rewritten
* `@truncate`'s fixup is incorrect for vectors
* Test cases are not formatted, and their error locations change
* Don't skip the TLS initialization (Fixes#9083)
* Add a test case where a PIE program is built and run
* Refactor the common initialization code in the Linux startup
sequence.
mlugg