Fix flaky GCN tests (#4693)

fix: flaky tests due to uninitialized values
fix: segfault during teardown while running gcn tests

fix: vulkan validation error by enabling shaderFloat16 in GCN runner

tests/gcn/gcn_test_runner.cpp

@@ -136,6 +136,11 @@ std::expected<Runner*, ErrorInfo> Runner::instance() {
     return g_runner.get();
 }
 
+void Runner::DestroyInstance() {
+    std::lock_guard lock{g_runner_mutex};
+    g_runner.reset();
+}
+
 std::expected<void, ErrorInfo> Runner::initialize() {
     VULKAN_HPP_DEFAULT_DISPATCHER.init();
 
@@ -223,6 +228,7 @@ std::expected<void, ErrorInfo> Runner::initialize() {
     vk::PhysicalDeviceVulkan12Features v12_feat{
         .pNext = &v11_feat,
         .uniformAndStorageBuffer8BitAccess = VK_TRUE,
+        .shaderFloat16 = VK_TRUE,
         .shaderInt8 = VK_TRUE,
     };
     vk::PhysicalDeviceFeatures phys_feat{

tests/gcn/gcn_test_runner.hpp

@@ -42,6 +42,7 @@ struct ErrorInfo {
 class Runner {
 public:
     static std::expected<Runner*, ErrorInfo> instance();
+    static void DestroyInstance();
 
     std::expected<void, ErrorInfo> run_raw(
         std::span<const std::uint32_t> spirv,

tests/gcn/instructions.hpp

@@ -1266,7 +1266,7 @@ private:
         u64 src2 : 9;
         u64 omod : 2;
         u64 neg : 3;
-    } i;
+    } i{};
 
     static_assert(sizeof(VOP3Internal) == sizeof(u64));
 };
@@ -1345,7 +1345,7 @@ private:
         u64 src2 : 9;
         u64 op_sel_hi01 : 2;
         u64 neg : 3;
-    } i;
+    } i{};
 
     static_assert(sizeof(VOP3PInternal) == sizeof(u64));
 };

tests/gcn/test_gcn_instructions.cpp

@@ -15,6 +15,10 @@ protected:
     void SetUp() override {}
 
     void TearDown() override {}
+
+    static void TearDownTestSuite() {
+        gcn_test::Runner::DestroyInstance();
+    }
 };
 
 struct F32x2 {