DUBAI, United Arab Emirates — Saudi Arabia is demolishing centuries-old homes in a Shiite town, leveling a historic district that officials say has become a hideout for local militants. The destruction has sparked shootouts in the streets between Saudi security forces and Shiite gunmen and stoked sectarian tensions that resonate around the region. At least six security officers, six Shiite gunmen and a number of civilians have been killed in al-Awamiya’s skirmishes, shootings and bombings this year, most of them in the weeks since government contractors began tearing down the town’s historical center. Police say a South Asian construction worker was killed by an improvised explosive device targeting the demolition workers.