cmd: update x/text to pull in CL 315571

Because x/text is now lazy, the go.sum file no longer needs a checksum
for the go.mod file for the outdated x/tools required by x/text.

For #36460
Updates #36905

Change-Id: Id7395e61909af3889c1615dc33139e5bb45504c5
Reviewed-on: https://go-review.googlesource.com/c/go/+/316490


Trust: Bryan C. Mills <bcmills@google.com>
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Alexander Rakoczy <alex@golang.org>