Revert "base: extend ImmediateCrashTest.ExpectedOpcodeSequence for mac arm64"

This reverts commit 8bb77f95.

Reason for revert: not a proper fix per mark's comments

Original change's description:
> base: extend ImmediateCrashTest.ExpectedOpcodeSequence for mac arm64
> 
> This test needs a case for what clang does on Mac Arm64, so add that.
> 
> Bug: 1128436,1121871
> Change-Id: I5d57f99f7d041bc91d9fc862c1d10ddc1b48f540
> Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2412552
> Commit-Queue: Nico Weber <thakis@chromium.org>
> Reviewed-by: Nico Weber <thakis@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#807243}

TBR=ellyjones@chromium.org,thakis@chromium.org

Change-Id: I32e706cd2544cd91974a39dc37f54438fe6822c2
No-Presubmit: true
No-Tree-Checks: true
No-Try: true
Bug: 1128436
Bug: 1121871
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2413562Reviewed-by: Elly Fong-Jones <ellyjones@chromium.org>
Commit-Queue: Elly Fong-Jones <ellyjones@chromium.org>
Cr-Commit-Position: refs/heads/master@{#807466}

base/immediate_crash_unittest.cc

@@ -150,13 +150,6 @@ TEST(ImmediateCrashTest, ExpectedOpcodeSequence) {
     // BRK #1
     EXPECT_EQ(0XD4200020, *++it);
 
-#elif defined(OS_MAC)
-
-    // BRK #1
-    EXPECT_EQ(0XD4200020, *++it);
-    // BRK #0
-    EXPECT_EQ(0XD4200000, *++it);
-
 #else
 
     // BRK #0