fix(scripting): stabilize mono wrapper test teardown

engine/src/Scripting/Mono/MonoScriptRuntime.cpp

@@ -29,6 +29,7 @@
 #include <mono/metadata/reflection.h>
 
 #include <algorithm>
+#include <cstdlib>
 #include <limits>
 #include <utility>
 
@@ -40,6 +41,7 @@ namespace {
 struct MonoRootState {
     MonoDomain* rootDomain = nullptr;
     bool initialized = false;
+    bool cleanupRegistered = false;
 };
 
 enum class ManagedComponentKind {
@@ -81,6 +83,19 @@ bool& GetInternalCallRegistrationState() {
     return registered;
 }
 
+void CleanupMonoRootDomainAtExit() {
+    MonoRootState& rootState = GetMonoRootState();
+    if (!rootState.rootDomain) {
+        return;
+    }
+
+    mono_domain_set(rootState.rootDomain, true);
+    mono_jit_cleanup(rootState.rootDomain);
+    rootState.rootDomain = nullptr;
+    rootState.initialized = false;
+    GetInternalCallRegistrationState() = false;
+}
+
 std::string BuildFullClassName(const std::string& namespaceName, const std::string& className) {
     return namespaceName.empty() ? className : namespaceName + "." + className;
 }
@@ -2455,6 +2470,10 @@ bool MonoScriptRuntime::InitializeRootDomain() {
     mono_domain_set(rootState.rootDomain, true);
     RegisterInternalCalls();
     rootState.initialized = true;
+    if (!rootState.cleanupRegistered) {
+        std::atexit(&CleanupMonoRootDomainAtExit);
+        rootState.cleanupRegistered = true;
+    }
     return true;
 }