[dev.power64] .hgignore: update for the 9 toolchain
[dev.power64] .hgignore: update for the 9 toolchain

LGTM=dave, rsc
R=rsc, iant, dave
CC=golang-codereviews
https://codereview.appspot.com/124840043

bryanxu/go-zh,d0f/go-zh,d0f/go-zh,webfd/go-zh,webfd/go-zh,bryanxu/go-zh,d0f/go-zh,bryanxu/go-zh,bryanxu/go-zh,bryanxu/go-zh,d0f/go-zh,webfd/go-zh,webfd/go-zh,webfd/go-zh,bryanxu/go-zh,d0f/go-zh,bryanxu/go-zh,webfd/go-zh,d0f/go-zh,bryanxu/go-zh,webfd/go-zh,webfd/go-zh,d0f/go-zh,d0f/go-zh