Makefile: add windowmanagertest to install file

Install the compiled windowmanagertest executable.

BUG=None
TEST=debbuild && check the created deb file.

Change-Id: I2d0a5a001d2af2f897a8d4d8eb44388df40c6e02
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/glbench/+/1889450
Tested-by: Po-Hsien Wang <[email protected]>
Auto-Submit: Po-Hsien Wang <[email protected]>
Reviewed-by: David Riley <[email protected]>
Legacy-Commit-Queue: Commit Bot <[email protected]>
Commit-Queue: Po-Hsien Wang <[email protected]>
1 file changed