Annotate intentionally unused result for std::variant nodiscard in absl_hardening_test.cc

Needed for https://github.com/llvm/llvm-project/pull/172058.

No behavior change.

Bug: 468205004
Change-Id: Ieca45ee3ef9832c313b0554d83c2d5e68e6deede
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7303050
Reviewed-by: Danil Chapovalov <danilchap@chromium.org>
Auto-Submit: Nico Weber <thakis@chromium.org>
Commit-Queue: Danil Chapovalov <danilchap@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1562182}
NOKEYCHECK=True
GitOrigin-RevId: 18cc2f904643c7859af18cb2c8e73448a022b8f7

absl_hardening_test.cc

diff --git a/absl_hardening_test.cc b/absl_hardening_test.cc
index 3d2ca55..2c3807d 100644
--- a/absl_hardening_test.cc
+++ b/absl_hardening_test.cc
@@ -74,8 +74,8 @@
 
 TEST(AbslHardeningTest, Variant) {
   absl::variant<int, std::string> variant = 5;
-  EXPECT_DEATH_IF_SUPPORTED(absl::get<std::string>(variant), "");
-  EXPECT_DEATH_IF_SUPPORTED(absl::get<1>(variant), "");
+  EXPECT_DEATH_IF_SUPPORTED(std::ignore = absl::get<std::string>(variant), "");
+  EXPECT_DEATH_IF_SUPPORTED(std::ignore = absl::get<1>(variant), "");
 }
 
 }  // namespace