[Fuzzer] Make Split's exports a list of strings

[aheejin]

When the export name contains a comma, such as foo<x,y>, the v8 command does not work:

v8 ... exports:foo<x,y>,bar,... --fuzz-split

This generates an exports as a list of strings within quotes, supporting export names with commas:

v8 ... exports:["foo<x,y>","bar",...] --fuzz-split

This still parses the old format of exports in case it doesn't contain commas, which I think might be useful for handwritten command lines.

[aheejin]

It's weird. Windows check hangs: https://github.com/WebAssembly/binaryen/actions/runs/26142999221/job/77013220649

[kripken]

The log says KeyboardInterrupt 😄 - who is clicking control-c in CI?

Does restarting the job help?

[aheejin]

Ah, maybe that was me. It took forever in the first try so I reran only that job in the CI panel but it also took forever so I merged main and made a new commit (so by adding a new commit the previous job was interrupted maybe) but the Window check is taking forever on this commit still. I wonder what in this PR can hang Windows..........

[aheejin]

I'll revert all changes in this PR just to make sure if my change is causing the issue.

[aheejin]

Not all checks are finished but the Windows-11-arm is done already: https://github.com/WebAssembly/binaryen/actions/runs/26197299501/job/77079404504?pr=8731

So this change causes Windows-11-arm (but not Windows-latest) to hang.... Why....

[stevenfontanella]

This windows run is also taking a while, so maybe there's some infra issue? https://github.com/WebAssembly/binaryen/actions/runs/26190799279/job/77058425164?pr=8625

[aheejin]

OK apparently other PRs have this Windows CI problem too: #8742, #8625, and #8743

[kripken]

Maybe this which just landed helps? #8749