cmd/tip: add App Engine Managed VM health check handler
cmd/tip: add App Engine Managed VM health check handler

Change-Id: I67826efaa3cb2883771837581dd95aa9ec3e6d2b
Reviewed-on: https://go-review.googlesource.com/18025
Reviewed-by: Brad Fitzpatrick <ae9783c0b0efc69cd85ab025ddd17aa44cdc4aa5@golang.org>

cmars/tools,golang/tools,syreclabs/go-tools,syreclabs/go-tools,cmars/tools,golang/tools,syreclabs/go-tools,golang/tools,golang/tools,syreclabs/go-tools,cmars/tools,syreclabs/go-tools,golang/tools,cmars/tools,syreclabs/go-tools