[TECHNICAL SUPPORT] LPS-51190 portlet_url.js generates wrong baseportleturl if context is set

https://issues.liferay.com/browse/LPS-51190

https://github.com/liferay/liferay-portal/blob/master/portal-impl/src/com/liferay/portal/events/ServicePreAction.java#L178

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https://github.com/liferay/liferay-portal/blob/master/portal-impl/src/com/liferay/portal/util/PortalImpl.java#L360

Regards,
Tibor