go: x/benchmarks/sweet/cmd/sweet: TestSweetEndToEnd failing with gvisor build errors since CL 386698

TestSweetEndToEnd is persistently failing on the linux-amd64-longtest and linux-amd64-perf builders since CL 386698 (attn @dr2chase, @prattmic, @aclements).

--- FAIL: TestSweetEndToEnd (181.32s)
    integration_test.go:128: no results produced.
    integration_test.go:150: command output:
        [sweet] Work directory: /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5
        [sweet] Benchmarks: gvisor
        [sweet] Setting up benchmark: gvisor
        [shell] git clone -b go https://github.com/google/gvisor /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/src
        [shell] git -C /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/src checkout 6392b0f3bea052af0de9d95677233dd9e442dbd5
        [shell] mkdir -p /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/results-5/gvisor
        [shell] mkdir -p /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/go/bin
        [shell] mkdir -p /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/src
        [shell] mkdir -p /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/go/tmp
        [shell] mkdir -p /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/go/assets
        [shell] cd /workdir/gopath/src/golang.org/x/benchmarks/sweet/benchmarks/gvisor
        [shell] /workdir/go/bin/go build -o /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/go/bin/gvisor-bench
        [shell] cd /workdir/gopath/src/golang.org/x/benchmarks/sweet/cmd/sweet
        [shell] cd /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/src/runsc
        [shell] CGO_ENABLED=0 /workdir/go/bin/go build -o /workdir/gopath/src/golang.org/x/benchmarks/sweet/tmp/tmp-5/gvisor/go/bin/runsc
        [shell] cd /workdir/gopath/src/golang.org/x/benchmarks/sweet/cmd/sweet
        [sweet] error: build gvisor for go: exit status 1
        [sweet] error: failed to execute benchmarks, see log for details
    integration_test.go:151: exit status 1
FAIL
FAIL	golang.org/x/benchmarks/sweet/cmd/sweet	181.334s

greplogs --dashboard -md -l -e 'error: build gvisor for .*: exit status 1'