RFR: 8295264: Fix PaX check on RISC-V

[Fei Yang]

On Mon, 17 Oct 2022 08:30:20 GMT, Ludovic Henry <luhenry at openjdk.org> wrote:

> > I see the LKML link mentions this: "Just remove the check altogether and let PROT_WRITE imply PROT_READ as is the case on other architectures.". Is this change still necessary then? Thanks.
> 
> That would be necessary for any older version of Linux. Also, it allows it to match all other calls to `::mmap` in hotspot.

That makes sence to me. Changes looks good to me.

-------------

PR: https://git.openjdk.org/jdk/pull/10690