runtime, time: don't use monotonic clock inside synctest bubbles
Don't include a monotonic time in time.Times created inside
a bubble, to avoid the confusion of different Times using
different monotonic clock epochs.
For #67434
goos: darwin
goarch: arm64
pkg: time
cpu: Apple M1 Pro
│ /tmp/bench.0 │ /tmp/bench.1 │
│ sec/op │ sec/op vs base │
Since-10 18.42n ± 2% 18.68n ± 1% ~ (p=0.101 n=10)
Until-10 18.28n ± 2% 18.46n ± 2% +0.98% (p=0.009 n=10)
geomean 18.35n 18.57n +1.20%
Change-Id: Iaf1b80d0a4df52139c5b80d4bde4410ef8a49f2f
Reviewed-on: https://go-review.googlesource.com/c/go/+/657415
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Damien Neil <dneil@google.com> Reviewed-by: Michael Pratt <mpratt@google.com>