[MSan] "Fix" use-after-dtor in InitializationState.InitializationState

Since the test is specifically trying to exercise UB by testing the
state of an object it is already destroyed, unpoison the memory to
suppress MSan errors.

Bug: 40222690
Change-Id: I840e944f5e8b39668ac05d8d641fdd5f2e3db5ac
Reviewed-on: https://chromium-review.googlesource.com/c/crashpad/crashpad/+/5716150
Reviewed-by: Mark Mentovai <[email protected]>

util/misc/initialization_state_test.cc

@@ -18,6 +18,7 @@
 
 #include <memory>
 
+#include "base/compiler_specific.h"
 #include "base/memory/free_deleter.h"
 #include "gtest/gtest.h"
 
@@ -59,6 +60,10 @@ TEST(InitializationState, InitializationState) {
   // buffer that’s still valid and its destructor was called directly, this
   // approximates use-after-free without risking that the memory formerly used
   // for the InitializationState object has been repurposed.
+
+  // (Though this is still UB and MSan does not like this)
+  MSAN_UNPOISON(initialization_state, sizeof(*initialization_state));
+
   EXPECT_FALSE(initialization_state->is_uninitialized());
   EXPECT_FALSE(initialization_state->is_valid());
 }