[resultui] Change Makefile to run npm install for build and test.
[resultui] Change Makefile to run npm install for build and test.

Bug: 1074016
Change-Id: I4dd897f2350668215cf5564a98899556e1590568
Reviewed-on: https://chromium-review.googlesource.com/c/infra/luci/luci-go/+/2166868
Auto-Submit: Joey Scarr <e609d4c46132d2dea94acf5ac2b9f229ffc1f245@chromium.org>
Reviewed-by: Weiwei Lin <968518a24f41fef00b747498600e52b792d06ae0@google.com>
Commit-Queue: Joey Scarr <e609d4c46132d2dea94acf5ac2b9f229ffc1f245@chromium.org>

luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go,luci/luci-go