Disable C++ exceptions when compile for wasm32-wasi

[glebpom]

Currently wasm32-wasi doesn't support exceptions

Checklist:

• All tests pass in CI.
• There are sufficient tests for the new fix/feature.
• Grammar rules have not been renamed unless absolutely necessary.
• The conflicts section hasn't grown too much.
• The parser size hasn't grown too much (check the value of STATE_COUNT in src/parser.c).

[maxbrunsfeld]

Thanks! We should actually disable exceptions for all C++ files in Tree-sitter parsers, regardless of what target you're compiling for. But this is fine for now.