[wasm] Fix UB in simd test

This was introduced in https://crrev.com/c/1703762.

R=titzer@chromium.org
CC=zhin@chromium.org

Change-Id: I3f13ab1ea1e87a2615883aa441581c62166f3587
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1709412Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#62822}

test/cctest/wasm/test-run-wasm-simd.cc

@@ -930,7 +930,7 @@ void RunF64x2UnOpTest(ExecutionTier execution_tier, LowerSimd lower_simd,
     r.Call(x);
     for (int i = 0; i < 2; i++) {
       double actual = ReadLittleEndianValue<double>(&g[i]);
-      CheckFloatResult(x, x, expected, actual, exact);
+      CheckDoubleResult(x, x, expected, actual, exact);
     }
   }