api.dis and decenc.drdecode_decenc_x86_64 failures in output matching

[derekbruening]

This seems to have started recently (though xref #5725):

x64 Linux:
https://github.com/DynamoRIO/dynamorio/actions/runs/6752187857/job/18358030169

420/473 Test #422: code_api|api.dis .................................................***Failed    0.10 sec
CMake Error at /home/runner/work/dynamorio/dynamorio/suite/tests/runcmp.cmake:114 (message):
  failed to match expected output

Same failure on win64:
https://github.com/DynamoRIO/dynamorio/actions/runs/6775123864/job/18413681364?pr=6410

Similarly obscure failure in the same win64 run:

297/303 Test #290: code_api|decenc.drdecode_decenc_x86_64 ...........................***Failed    2.10 sec
CMake Error at D:/a/dynamorio/dynamorio/suite/tests/runcmp.cmake:114 (message):
  failed to match expected output

Did we change runcmp.cmake to not print out the diff?
I think PR #6254 is the culprit: that is why we now just have this opaque
message without details. So these may be the same as #5725.

[derekbruening]

From #6428 (comment) adding the diff: this does look like #5725 so let's collapse into that one.

[leewvic]

Attaching a diff output for the decoder problem. Current theory: there are some difference how AMD vs. Intel machines interpret the opcodes.
6_Run Suite.txt