Arm backend: Move tosa-dialect tests into package

[oscarandersson8218]

cc @digantdesai @freddan80 @per @zingo @mansnils @Sebastian-Larsson @robell @rascani

[pytorch-bot]

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⏳ 1 Pending, 2 Unrelated Failures

As of commit 5cdf800 with merge base a142873 ():

FLAKY - The following job failed but was likely due to flakiness present on trunk:

• RISC-V / test-riscv / run / linux-job (gh) (matched linux rule in flaky-rules.json)
  The process '/usr/bin/git' failed with exit code 128

BROKEN TRUNK - The following job failed but was present on the merge base:

👉 Rebase onto the `viable/strict` branch to avoid these failures

• trunk / test-models-macos-coreml (dl3) / macos-job (gh) (trunk failure)
  RuntimeError: Command bash /Users/ec2-user/runner/_work/_temp/exec_script failed with exit code 1

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[oscarandersson8218]

PR shouldn't require any further bzl or BUCK changes.