[clang] [clang-repl] Support wasm execution (PR #86402)

[Aaron Ballman via cfe-commits]

AaronBallman wrote:

So are we in a chicken-and-egg situation where we need some support in-tree in order to have a reason to set up a postcommit test bot but we don't want to land untested changes?

At the end of the day, if we're claiming support for something, we need it to be tested and this seems like a situation where we'd need an actual buildbot specific for the need. So we may want to proceed here in a few stages: 1) push up these changes without testing, 2) get a bot set up and have it test these changes, once it's green and we're happy then we publicly claim support, 3) if we don't get a bot set up within some reasonable timeframe, we agree to remove these changes so we don't leave untested code in the repo.

WDYT?

https://github.com/llvm/llvm-project/pull/86402