Check PAL_VirtualUnwind failure during GC (#6598)

As discussed in #6525, PAL_VirtualUnwind sometimes fails during GC.

This GC failure leads to very unpredicatble behavior (which is very hard to
analyze).

This commit tries to stop the execution at the point where error
happens.

Author: parjong

src/vm/amd64/gmsamd64.cpp

@@ -62,7 +62,12 @@ void LazyMachState::unwindLazyState(LazyMachState* baseState,
             DacError(hr);
         }
 #else
-        PAL_VirtualUnwind(&ctx, &nonVolRegPtrs);
+        BOOL success = PAL_VirtualUnwind(&ctx, &nonVolRegPtrs);
+        if (!success)
+        {
+            _ASSERTE(!"unwindLazyState: Unwinding failed");
+            EEPOLICY_HANDLE_FATAL_ERROR(COR_E_EXECUTIONENGINE);
+        }
 #endif  // DACCESS_COMPILE    
 
         pvControlPc = GetIP(&ctx);

src/vm/arm/stubs.cpp

@@ -544,7 +544,12 @@ void LazyMachState::unwindLazyState(LazyMachState* baseState,
             DacError(hr);
         }
 #else // DACCESS_COMPILE
-        PAL_VirtualUnwind(&ctx, &nonVolRegPtrs);
+        BOOL success = PAL_VirtualUnwind(&ctx, &nonVolRegPtrs);
+        if (!success)
+        {
+            _ASSERTE(!"unwindLazyState: Unwinding failed");
+            EEPOLICY_HANDLE_FATAL_ERROR(COR_E_EXECUTIONENGINE);
+        }
 #endif // DACCESS_COMPILE
         pvControlPc = GetIP(&ctx);
 #endif // !FEATURE_PAL

src/vm/arm64/stubs.cpp

@@ -330,7 +330,12 @@ void LazyMachState::unwindLazyState(LazyMachState* baseState,
             DacError(hr);
         }
 #else // DACCESS_COMPILE
-        PAL_VirtualUnwind(&context, &nonVolContextPtrs);  
+        BOOL success = PAL_VirtualUnwind(&ctx, &nonVolContextPtrs);
+        if (!success)
+        {
+            _ASSERTE(!"unwindLazyState: Unwinding failed");
+            EEPOLICY_HANDLE_FATAL_ERROR(COR_E_EXECUTIONENGINE);
+        }
 #endif // DACCESS_COMPILE
         pvControlPc = GetIP(&context);
 #endif // !FEATURE_PAL