[gwp_asan] Employ EXPECT_DEATH for zxtest compatibility

Employ a similar tactic introduced by https://reviews.llvm.org/D94362
for gwp_asan tests. zxtest `ASSERT_DEATH` syntax differs from gtest in
that it expects a lambda.

zxtest does not have `EXPECT_DEATH`, so it introduced for Fuchsia builds
and wraps the expression with a lambda to create a compatible syntax
between zxtest and gtest for death tests.

An example of where this compatiblity is needed is in
`never_allocated.cpp`.

Differential Revision: https://reviews.llvm.org/D147189

GitOrigin-RevId: f2a1726d2199150918430a84f29cf8835bfe8e5a

tests/harness.h

diff --git a/tests/harness.h b/tests/harness.h
index 3e85935..ae39a44 100644
--- a/tests/harness.h
+++ b/tests/harness.h
@@ -15,6 +15,13 @@
 #define ZXTEST_USE_STREAMABLE_MACROS
 #include <zxtest/zxtest.h>
 namespace testing = zxtest;
+// zxtest defines a different ASSERT_DEATH, taking a lambda and an error message
+// if death didn't occur, versus gtest taking a statement and a string to search
+// for in the dying process. zxtest doesn't define an EXPECT_DEATH, so we use
+// that in the tests below (which works as intended for gtest), and we define
+// EXPECT_DEATH as a wrapper for zxtest's ASSERT_DEATH. Note that zxtest drops
+// the functionality for checking for a particular message in death.
+#define EXPECT_DEATH(X, Y) ASSERT_DEATH(([&] { X; }), "")
 #else
 #include "gtest/gtest.h"
 #endif

tests/never_allocated.cpp

diff --git a/tests/never_allocated.cpp b/tests/never_allocated.cpp
index bd43b22..2f695b4 100644
--- a/tests/never_allocated.cpp
+++ b/tests/never_allocated.cpp
@@ -25,7 +25,7 @@
   // in the posix crash handler.
   char *volatile NeverAllocatedPtr = static_cast<char *>(Ptr) + 0x3000;
   if (!Recoverable) {
-    ASSERT_DEATH(*NeverAllocatedPtr = 0, DeathNeedle);
+    EXPECT_DEATH(*NeverAllocatedPtr = 0, DeathNeedle);
     return;
   }