By Dawoud Abu Alkas GAZA CITY, June 22 (Reuters) - Residents of the Gaza Strip have been flocking from suffocating tents to the territory's polluted Mediterranean shore to bathe and wash their clothes, as summer temperatures rise and fresh water remains hard to come by. Nearly all Gaza's population was displaced during two years of war between Israel and Hamas, with Gazans now crammed into a narrow strip along the coast, mainly in tents and damaged buildings.