By Timour Azhari, Ahmed Rasheed and Humeyra PamukRIYADH/BAGHDAD/WASHINGTON, May 13 (Reuters) - Saudi fighter jets bombed targets linked to powerful Tehran-backed Shi'ite militias in Iraq during the Iran war, while retaliatory strikes were also launched from Kuwait into Iraq, multiple sources familiar with the matter said.The strikes are part of a broader pattern of military responses around the Gulf that remained largely hidden during a conflict that has drawn in the wider Middle East since join...