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

[Vassil Vassilev via cfe-commits]

vgvassilev wrote:

@AaronBallman, to be fair, clang is testing the wasm features in terms of output. So this is wiring up a bunch of tested features that will allow execution. Clang generally does not test execution but output, so we are not creating a precedent here since that PR can be considered plumbing for downstream consumers. 

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