Fix calling convention mismatch in GC callouts (dotnet#110685)

Fixes dotnet#110607.

The native side expected fastcall, managed side didn't.

Filed dotnet#110684 on the test hole. We would have caught it during x86 bringup if this had _any_ tests since this is a guaranteed stack corruption and crash.

src/coreclr/nativeaot/Runtime/RestrictedCallouts.h

@@ -97,6 +97,6 @@ class RestrictedCallouts
     static CrstStatic s_sLock;
 
     // Prototypes for the callouts.
-    typedef void (F_CALL_CONV * GcRestrictedCallbackFunction)(uint32_t uiCondemnedGeneration);
+    typedef void (* GcRestrictedCallbackFunction)(uint32_t uiCondemnedGeneration);
     typedef CLR_BOOL (* HandleTableRestrictedCallbackFunction)(Object * pObject);
 };