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

[Aleksey Shipilev]

On 11/22/18 3:14 PM, Roland Westrelin wrote:
> http://cr.openjdk.java.net/~roland/8214206/webrev.00/
> 
> The log2_intptr(int x) and log2_intptr(intptr_t x) conflict on 32 bit.

I don't think conditional compilation is the answer here. It seems better to have declarations that
are guaranteed not to clash. For example:
  http://cr.openjdk.java.net/~shade/8214206/webrev.00/

This builds on x86_32 and x86_64 without problems. STATIC_ASSERTS help to find the jlong downcast
issue Goetz mentioned in his note, and I believe the answer is "unsigned long long". Roland, feel
free to use this patch either partially or in full.

-Aleksey