[liftoff] Fix float stability issue on arm simulator

On intel platforms, floats do not always have a stable bit pattern.
To preserve the bit pattern of float immediates, we should keep them
in an int using get_bits() instead of casting them to a float with
get_scalar().

R=ahaas@chromium.org
CC=​zhin@chromium.org

Change-Id: I481219f755c40cbba760be5744734c1075e8ab66
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2172694
Commit-Queue: Thibaud Michaud <thibaudm@chromium.org>
Reviewed-by: Andreas Haas <ahaas@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67560}

src/wasm/baseline/arm/liftoff-assembler-arm.h

@@ -355,7 +355,7 @@ void LiftoffAssembler::LoadConstant(LiftoffRegister reg, WasmValue value,
       break;
     case ValueType::kF64: {
       Register extra_scratch = GetUnusedRegister(kGpReg).gp();
-      vmov(reg.fp(), Double(value.to_f64_boxed().get_scalar()), extra_scratch);
+      vmov(reg.fp(), Double(value.to_f64_boxed().get_bits()), extra_scratch);
       break;
     }
     default: