[traphandler] Fix test link errors on some MSan/ASan builds

Found these when compiling the arm64 simulator for MSan (Release) and
ASan (Debug and Release). Depending on the exact configuration (and
compiler), different functions will get inlined and different symbols
need to be available at link time.

1) Since GetRecoveredTrapCount is used in a unittest, it needs to be
   exported.

2) The thread-local g_thread_in_wasm_code cannot be exported on
   Windows, hence it cannot (safely) be used in unit tests. Use the
   {GetThreadInWasmThreadLocalAddress} function instead, which will
   return the address of that thread-local variable.

R=ahaas@chromium.org, mseaborn@chromium.org

Bug: v8:11955
Change-Id: I118f60c1580a8362f8232541576a1c41da7042bd
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3049077Reviewed-by: Andreas Haas <ahaas@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75960}

src/trap-handler/trap-handler.h

@@ -153,7 +153,7 @@ inline void ClearThreadInWasm() {
 bool RegisterDefaultTrapHandler();
 TH_EXPORT_PRIVATE void RemoveTrapHandler();
 
-size_t GetRecoveredTrapCount();
+TH_EXPORT_PRIVATE size_t GetRecoveredTrapCount();
 
 }  // namespace trap_handler
 }  // namespace internal

test/unittests/wasm/trap-handler-simulator-unittest.cc

@@ -23,15 +23,17 @@ constexpr uintptr_t kFakePc = 11;
 
 class SimulatorTrapHandlerTest : public TestWithIsolate {
  public:
-  static void SetThreadInWasm() {
-    EXPECT_EQ(0, g_thread_in_wasm_code);
-    g_thread_in_wasm_code = 1;
+  void SetThreadInWasm() {
+    EXPECT_EQ(0, *thread_in_wasm);
+    *thread_in_wasm = 1;
   }
 
-  static void ResetThreadInWasm() {
-    EXPECT_EQ(1, g_thread_in_wasm_code);
-    g_thread_in_wasm_code = 0;
+  void ResetThreadInWasm() {
+    EXPECT_EQ(1, *thread_in_wasm);
+    *thread_in_wasm = 0;
   }
+
+  int* thread_in_wasm = trap_handler::GetThreadInWasmThreadLocalAddress();
 };
 
 TEST_F(SimulatorTrapHandlerTest, ProbeMemorySuccess) {