misc/chrome/gophertool: lower CL number's lower bound and fix input focus on Mac
As our CL number could be as small as 152046, changed CL number's lower bound
to 150000. Hopefully our issue count won't reach 150000 any time soon.
Chrome on Mac OS X has very strange behavior regarding the focus, although we
force the focus to the input box on load, the page still come up with focus on
"issue". Set the tabindex of the input box as a workaround.
R=golang-dev, bradfitz
CC=golang-dev
https://golang.org/cl/
6212055