Israel and the United States are signing an agreement Wednesday to develop and produce jointly a new surface-to-air missile to counter a growing Arab missile and chemical weapons arsenal. The agreement is being signed at the Pentagon by Gen. David Ivry, director general of the Israeli defense ministry, and Lt. Gen. James Abrahamson, director of the U.S. Strategic Defense Initiative Organization. The signing follows a statement of concern issued Tuesday by President Reagan after a meeting at the White House with Israeli Defense Minister Yitzhak Rabin. The president said he was troubled by "ominous new military developments" in the area.