NEW YORK (Reuters) - The U.S. dollar fell against the Japanese yen on Thursday as investors pushed into safe-haven assets on reports the United States and China were struggling to finalise a "phase one" trade deal and as the domestic impeachment inquiry into U.S. President Donald Trump intensified.The Japanese yen was up 0.39% to 108.4 against the dollar, having risen to a 10-day high earlier in the session. The Swiss franc also benefited, up 0.16%, with the dollar index down 0.22% to 98.159...