i#5036 A64 scatter/gather, part 6: Expand multi-register instrs

[jackgallagher-arm]

Adds support to drx_expand_scatter_gather() for SVE multi-register scalar+scalar and scalar+immediate predicated contiguous load and store instructions, along with tests.

Issue: #5036

[jackgallagher-arm]

@derekbruening @abhinav92003, could you take a look at this PR when you have an opportunity. Thanks.

[abhinav92003]

@derekbruening @abhinav92003, could you take a look at this PR when you have an opportunity. Thanks.

Wow this one seems to have been pending from my side for 2 weeks. Apologies for the delay. I'll get this done by today or latest tomorrow (since it's a bit on the long side).

[jackgallagher-arm]

The consistent ci-x86/x86-32 failure looks like it is due to #6417

[abhinav92003]

The consistent ci-x86/x86-32 failure looks like it is due to #6417

I can merge this PR when the CI completes.

[abhinav92003]

I'm seeing new issues on the burst_traceopts test on vs2019-64:

2023-11-21T15:50:33.0935549Z 267:   D:\a\dynamorio\dynamorio\build_debug-internal-64\clients\bin64\tool.drcacheoff.burst_traceopts.exe
2023-11-21T15:50:33.0937319Z 267:   (712) DynamoRIO usage error : internal isa mode error>
2023-11-21T15:50:33.0938001Z 267: 
2023-11-21T15:50:33.0938785Z 267:   <Usage error: internal isa mode error
2023-11-21T15:50:33.0939603Z 267:   (D:\a\dynamorio\dynamorio\core\ir\decode_shared.c, line 281)

and

2023-11-21T15:50:33.1036394Z 267:   D:\a\dynamorio\dynamorio\build_debug-internal-64\clients\bin64\tool.drcacheoff.burst_traceopts.exe
2023-11-21T15:50:33.1037652Z 267:   (1056).  Internal Error: DynamoRIO debug check failure:
2023-11-21T15:50:33.1038527Z 267:   D:\a\dynamorio\dynamorio\core\win32\callback.c:3404 false
2023-11-21T15:50:33.1054071Z 267: 
2023-11-21T15:50:33.1058780Z 267:   (Error occurred @18 frags in tid 2076)

Doesn't seem to be the same as #6423.

On the same test in a re-run, I also saw #6423 and

2023-11-21T15:09:42.4290110Z CMake Error at D:/a/dynamorio/dynamorio/suite/tests/runmulti.cmake:135 (message):
2023-11-21T15:09:42.4291535Z   output |Trace mismatch found: Trace types do not match: 10 vs 14
2023-11-21T15:09:42.4292293Z 
2023-11-21T15:09:42.4292547Z   all done
2023-11-21T15:09:42.4292903Z 
2023-11-21T15:09:42.4293274Z   | failed to match expected output |^all done

[abhinav92003]

Okay vs2019-64 passed on a re-run. Submitting.

[jackgallagher-arm]

Thanks @abhinav92003 .