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This is a reland of 28eb992f

Fixes:
- Disable sanitizers in the test helper. The test is intended to test
  baseline behavior with max optimizations/undefined behavior, and the
  assumption is that sanitized builds will, in fact, be saner.
- Relax the nonce check, as the compiler can reorder IMMEDIATE_CRASH()
  blocks in the function epilogue as it wants.

Original change's description:
> Add test to verify the opcodes generated by IMMEDIATE_CRASH().
>
> Bug: 958675
> Change-Id: Ica6b5bab7849f227567d8016354a39383533799f
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1595585
> Commit-Queue: Daniel Cheng <dcheng@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#658344}

Bug: 958675
Change-Id: Ic1af1994909d58427cc12f1f9aee2765aa5b449c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1604487
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#658523}