cmd/go: specify full path to go command when running go tool covdata

Otherwise the GOROOT will be a post-1.25 GOROOT, while we try to run
"go tool covdata" with a go command that's 1.24 or earlier from the post
1.25 toolchain. The 1.24 go command won't be able to find covdata in the
1.25 goroot because go 1.25 and later don't ship with a prebuilt covdata
tool.

For #71867
Fixes #75031

Change-Id: I770f10a288347ac33cf721d34a2adb1a6a6a6964
Reviewed-on: https://go-review.googlesource.com/c/go/+/756220
Reviewed-by: Dmitri Shuralyov <dmitshur@golang.org>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Michael Matloob <matloob@google.com>
Reviewed-by: Dmitri Shuralyov <dmitshur@google.com>

0 files changed, 0 insertions, 0 deletions