fix function signature of v128.pmin, v128.pmax

[JesseCodeBones]

according to the source code of builtin_v128_pmin and builtin_v128_pmax.
they only accept the f32 and f64 format, change the function signature according to its source code.

  if (type.isValue) {
    switch (type.kind) {
      case TypeKind.F32: return module.binary(BinaryOp.PminF32x4, arg0, arg1);
      case TypeKind.F64: return module.binary(BinaryOp.PminF64x2, arg0, arg1);
    }
  }
  compiler.error(
    DiagnosticCode.Operation_0_cannot_be_applied_to_type_1,
    ctx.reportNode.typeArgumentsRange, "v128.pmin", type.toString()
  );

this issue found from issue 2374

• I've read the contributing guidelines
• I've added my name and email to the NOTICE file

[MaxGraey]

Thanks for PR. I'm wondering why all your PRs started as "Optimize ..." while it just fixes, some improvements in tests or type definitions? =) It's a little confusing.

[JesseCodeBones]

yes, OK, I will add tests and change the title

[JesseCodeBones]

@MaxGraey
Hi Max,
I am not familiar the wat generation flow, now it should be OK, please kindly review.