Revisit usage of ThrowExceptionForHR

[tmat]

This: hr != HResult.E_FAIL is suspicious.

        internal static void ThrowExceptionForHR(int hr)
        {
            // E_FAIL indicates "no info".
            // E_NOTIMPL indicates a lack of ISymUnmanagedReader support (in a particular implementation).
            if (hr < 0 && hr != HResult.E_FAIL && hr != HResult.E_NOTIMPL)
            {
                Marshal.ThrowExceptionForHR(hr, s_ignoreIErrorInfo);
            }
        }