x/build: `android-.*-emu` builder failures with `adb: error: connect failed: closed`

[bcmills]

#!watchflakes
post <- builder ~ `android-.*` && log ~ `adb: error: connect failed: closed`

adb push /workdir/tmp/go_android_exec-cmd-go-3350234747 /data/local/tmp/go_android_exec/goroot/bin/go
adb: error: connect failed: closed
go_android_exec: exit status 1
FAIL	golang.org/x/benchmarks/cmd/bent	27.763s

greplogs -l -e 'adb: error: connect failed: closed'
2022-05-04T20:30:17-39d8c21-e1e056f/android-amd64-emu
2022-03-18T06:03:39-0e9765c-3d19e8d/android-386-emu
2021-10-18T21:21:54-ffe10e5-6c0daa7/android-amd64-emu
2021-03-26T06:03:03-6b15177-9c7463c/android-amd64-emu

(attn @golang/android)

[bcmills]

Since this only affects the -emu builders, I wonder if this is a defect in the emulator itself.

Perhaps the builder image should be updated with a more recent emulator, or the bug should be escalated to the Android emulator developers?

[bcmills]

FWIW, it looks like our go_android_exec wrapper explicitly waits for the emulator to boot:
https://cs.opensource.google/go/go/+/master:misc/android/go_android_exec.go;l=94-99;drc=98f3d7fecbb8a9074f5f4ffc50bb016e194940b7

[gopherbot]

Change https://go.dev/cl/412174 mentions this issue: dashboard: add known issues for android-*-emu

[gopherbot]

Change https://go.dev/cl/465156 mentions this issue: dashboard: unmark known-issues with low failure rates