JIT: don't optimize calls to CORINFO_HELP_VIRTUAL_FUNC_PTR

The jit currently replaces calls to `CORINFO_HELP_VIRTUAL_FUNC_PTR`
whose results are unused with null pointer checks.

But this helper can now throw a variety of exceptions, so this
optimization is incorrect.

Fixes dotnet#82127.

src/coreclr/jit/morph.cpp

@@ -7802,25 +7802,6 @@ GenTree* Compiler::fgMorphCall(GenTreeCall* call)
 #endif
     }
 
-    if ((call->gtCallMoreFlags & GTF_CALL_M_SPECIAL_INTRINSIC) == 0 &&
-        (call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_VIRTUAL_FUNC_PTR)
-#ifdef FEATURE_READYTORUN
-         || call->gtCallMethHnd == eeFindHelper(CORINFO_HELP_READYTORUN_VIRTUAL_FUNC_PTR)
-#endif
-             ) &&
-        (call == fgMorphStmt->GetRootNode()))
-    {
-        // This is call to CORINFO_HELP_VIRTUAL_FUNC_PTR with ignored result.
-        // Transform it into a null check.
-
-        assert(call->gtArgs.CountArgs() >= 1);
-        GenTree* objPtr = call->gtArgs.GetArgByIndex(0)->GetNode();
-
-        GenTree* nullCheck = gtNewNullCheck(objPtr, compCurBB);
-
-        return fgMorphTree(nullCheck);
-    }
-
     noway_assert(call->gtOper == GT_CALL);
 
     //