Further AArch64 Support & Syscall OS Nuance Fixes

[FinnWilkinson]

This pull request mainly contains aditional AArch64 instructions (inc. sve) and syscalls needed by the TeaLeaf benchmark (this branch was rebased onto the TeaLeaf-benchmark branch).

There are also some fixes to :

• Syscall issues that arrose when running SimEng on MacOS as well as Isambard
• Minor fixex to deal wth sanitizer errors
• Fixed minor errors that arrose from invalid speculated instructions
• Ammended SCVTF and FCVT sve implementations and added more relevant test cased

[FinnWilkinson]

Faccessat syscall test failing poissibly due to different file structure on Jenkins. Filepath used in test needs re-evaluating and/or print statements need pushing to PR to evaluate where in file directory the tests are being executed from

• Want test to be relative to the current working directory as we need to test that the use of AT_FDCWD as the dirfd works correctly
• The current implementation works on my local machine, but was initially failing when executing the tests in different ways due to differing CWD; so the same thing is probably happening on the Jenkins pipeline

[FinnWilkinson]

No more commits are expected for this PR other than to fix issues brought up when reviewing.

[FinnWilkinson]

#rerun tests

[jj16791]

#rerun tests