cmd/ld: do not relocate ignored PE sections
cmd/ld: do not relocate ignored PE sections

This should have been part of CL8715043.

Update issue 5106

R=golang-dev, r, iant
CC=golang-dev
https://codereview.appspot.com/8676050

h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang,h8liu/golang