After JDK-8278337, the definition of `bitset_to_fregs` is just same as `bitset_to_regs`.

bitset_to_regs：
```
int MacroAssembler::bitset_to_regs(unsigned int bitset, unsigned char* regs) {
  int count = 0;
  // Scan bitset to accumulate register pairs
  for (int reg = 31; reg >= 0; reg--) {
    if ((1U << 31) & bitset) {
      regs[count++] = reg;
    }
    bitset <<= 1;
  }
  return count;
}
```

bitset_to_fregs:
```
int MacroAssembler::bitset_to_fregs(unsigned int bitset, unsigned char* regs) {
  int count = 0;
  // Scan bitset to accumulate register pairs
  for (int reg = 31; reg >= 0; reg--) {
    if ((1U << 31) & bitset) {
      regs[count++] = reg;
    }
    bitset <<= 1;
  }
  return count;
}
```