[WebAssembly][clang][lld] None Legacy EH does not look working correctly

we need to do soething like this
```
-fwasm-exceptions -Wl,-mllvm,-wasm-enable-eh -Wl,-mllvm,-wasm-use-legacy-eh=false
```
still no guarantee to work.

also if we just use -Wl-mllvm,-wasm-enable-eh without -fwasm-exceptions. Compiler will crash.

```
[otgnhon doublefreetest]$ clang++ -o fr_neweh2.wasm fr.cc -O3 --target=wasm32-wasip1 --sysroot=$HOME/toolchains/llvm/wasm32-wasip1/wasm32-wasip1 -fwasm-exceptions -Wl,-mllvm,-wasm-enable-eh -Wl,-mllvm,-wasm-use-legacy-eh=false -lc++abi -lunwind -s
wasm-ld: error: symbol type mismatch: __cpp_exception
>>> defined as WASM_SYMBOL_TYPE_TAG in /tmp/fr-a80426.o
>>> defined as WASM_SYMBOL_TYPE_FUNCTION in /home//toolchains/llvm/wasm32-wasip1/wasm32-wasip1/lib/wasm32-wasip1/libunwind.a(Unwind-wasm.c.obj)
clang++: error: linker command failed with exit code 1 (use -v to see invocation)
[otgnhon doublefreetest]$ clang++ -o fr_neweh2.wasm fr.cc -O3 --target=wasm32-wasip1 --sysroot=$HOME/toolchains/llvm/wasm32-wasip1/wasm32-wasip1 -fwasm-exceptions -Wl,-mllvm,-wasm-enable-eh -Wl,-mllvm,-wasm-use-legacy-eh=false -lc++abi -lunwind -flto=thin -s
`````
but lto works which is ridiculous

Start by reproducing the two clang++ commands using fr.cc, the wasm32-wasip1 target, and the shown exception and linker flags. Compare the non-LTO and ThinLTO results, then trace the clang/lld handling of legacy versus new WebAssembly EH and the __cpp_exception symbol. Done means the reported mismatch and crash are understood and the affected configuration behaves consistently.

Written by the indexing model from the issue text.