Investigate and update auxv flags on Z for processor recognition

[r30shah]

While reviewing PR, we saw that auxv flags are not updated after Guarded Storage check for Linux on IBM Z (#7112 (comment)).

Though, on the OMR Port library, it will check the STFLE bits and some of the features that are not updated does not need OS check for the exploitation.

A note from Joran,

We will need to confirm under which kernel levels these HWCAPs will be updated. Otherwise, we risk assuming that the features are unavailable if the respective hwcap bits are not set. As such, while I think we can update the list in [2] to be more comprehensive, I don't think we should add these extra hwcap tests, unless our min kernel levels are guaranteed to properly set the tested hwcap bits.

Opening up this issue to investigate and update the flags for Linux on IBM Z.