strange decoder and other test failures in some x86-64 GA CI runs

One x86-64 run in PR #5723 (which changes just a few bbdup asm test files and so should not affect anything else) suddenly had 4 failures. They went away on a re-run.

The decoding ones are weird:

https://github.com/DynamoRIO/dynamorio/actions/runs/3430785437/jobs/5718556145

385/434 Test #386: code_api|api.dis .............................................***Failed    0.07 sec
-- diff: 1301c1301
< +0x0c7d   66 72 79             jb     0x0000000000000cf9
---
> +0x0c7d   66 72 79             jb     0x0000000010000cf9
1968c1968
< +0x1322   66 7c f6             jl     0x000000000000131b
---
> +0x1322   66 7c f6             jl     0x000000001000131b
2426c2426
< +0x17ea   4c ff 69 f6          jmp    fword ptr [rcx-0x0a]
---
> +0x17ea   4c ff 69 f6          jmp    tbyte ptr [rcx-0x0a]
2995c2995
< +0x1d87   66 77 39             jnbe   0x0000000000001dc3
---
> +0x1d87   66 77 39             jnbe   0x0000000010001dc3

CMake Error at /home/runner/work/dynamorio/dynamorio/suite/tests/runcmp.cmake:86 (message):
  output in
  /home/runner/work/dynamorio/dynamorio/build_debug-internal-64/suite/tests/dis-x64.expect-out
  failed to match expected output in
  /home/runner/work/dynamorio/dynamorio/build_debug-internal-64/suite/tests/dis-x64.expect-expect

171/434 Test #169: code_api|client.attach_test ..................................***Failed  Required regular expression not found. Regex=[^starting
thank you for testing attach
thread init
event_post_attach
done
$
]  0.24 sec
CMake Error at /home/runner/work/dynamorio/dynamorio/suite/tests/runall.cmake:124 (message):
  *** kill failed (1): kill: (23301): No such process

393/434 Test #394: code_api|decenc.drdecode_decenc_x86_64 .......................***Failed    1.09 sec
-- diff: 6581,6584c6581,6583
<  66 e9 00 00          data16 jmp    $0x0000000000007b3f
<  89 c3                mov    %eax, %ebx
<  66 e8 00 00          data16 call   $0x0000000000007b45
<  66 e9 00 00          data16 jmp    $0x0000000000007b49
---
>  66 e9 00 00 89 c3    data16 jmp    $0xffffffffd3897b41
>  66 e8 00 00 66 e9    data16 call   $0xfffffffff9667b47
>  00 00                add    %al, (%rax)
6586,6590c6585,6589
<  66 e8 00 00          data16 call   $0x0000000000007b4f
<  66 ff d0             data16 call   %ax
<  66 ff 10             data16 call   (%rax)
<  66 ff e0             data16 jmp    %ax
<  66 ff e0             data16 jmp    %ax
---
>  66 e8 00 00 66 ff    data16 call   $0x000000000f667b51
>  d0 66 ff             shlb   $0x01, -0x01(%rsi)
>  10 66 ff             adc    %ah, -0x01(%rsi)
>  e0 66                loopne $0x0000000010007bbf
>  ff e0                jmp    %rax

 26/434 Test  #23: code_api|common.floatpc_xl8all ...............................***Failed  Required regular expression not found. Regex=[^FXSAVE64 intra is correctly handled
FXSAVE64 inter is correctly handled
FXSAVE intra is correctly handled
FXSAVE inter is correctly handled
$
]  0.21 sec
FXSAVE64 intra is correctly handled
FXSAVE64 inter is **incorrectly** handled
FXSAVE intra is correctly handled
FXSAVE inter is **incorrectly** handled