RFR(T): 8214206: Fix for JDK-8213419 is broken on 32-bit

[Roland Westrelin]

Hi Goetz,

> isn't this wrong, too:
>
>  inline int log2_long(jlong x) {
>    return log2_long((unsigned long)x);
>  }
>
> It casts the 64-bit x to 32 bit on 32 bit architectures.

Yes, it's wrong. It also causes JDK-8214189. Which is the bug I intend
to use it to fix it.

Roland.