[wasm-simd] Fix endianness issue on BitMask interpreter

Change-Id: I92223e6b42a3ab80d0f0a4dab4dc20d7d7f1a6ca
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2220329Reviewed-by: Zhi An Ng <zhin@chromium.org>
Commit-Queue: Milad Farazmand <miladfar@ca.ibm.com>
Cr-Commit-Position: refs/heads/master@{#68057}

src/wasm/wasm-interpreter.cc

@@ -2363,7 +2363,7 @@ class ThreadImpl {
     stype s = v.to_s128().to_##name();                                  \
     int32_t res = 0;                                                    \
     for (size_t i = 0; i < count; ++i) {                                \
-      bool sign = std::signbit(static_cast<double>(s.val[i])); \
+      bool sign = std::signbit(static_cast<double>(s.val[LANE(i, s)])); \
       res |= (sign << i);                                               \
     }                                                                   \
     Push(WasmValue(res));                                               \