Remove QUIC_EXPORT from QuicIntervalDeque and member classes because every symbol is defined in this compilation unit. Thank you dschinazi@ for reminding me of this rule at b/148069436#comment10. gfe-relnote: n/a (QUIC_EXPORT macro is no-op in Google3) PiperOrigin-RevId: 297734661 Change-Id: I5054a59d591298b621e2f8d4deea4e7a6c8f7f83