RFR: 8265473: Move os::Linux to its own header file [v4]

[David Holmes]

On Sat, 9 Jul 2022 23:27:31 GMT, Ioi Lam <iklam at openjdk.org> wrote:

>> Another step of moving unnecessary stuff outside of os.hpp
>> 
>> The `os::Linux` class is used only by the Linux-specific code in HotSpot. Therefore, it should be moved outside of os.hpp, which is used by platform-independent code.
>> 
>> I don't have a good name for the new header. `os_linux.hpp` would have been a good name, but that's already taken, so I am settling on os_linux.impl.hpp. Suggestions are welcome.
>
> Ioi Lam has updated the pull request incrementally with one additional commit since the last revision:
> 
>   renamed to os_linux_impl.hpp

AllStatic is just a way to say that a Class has all static methods - no per-instance state. No different IMO to a singleton class, just without the overhead of creating an instance.

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PR: https://git.openjdk.org/jdk/pull/9423