trace: regenerate trace from go@81d424e

[git-generate]
cd trace
./gen.bash $HOME/work/go-1

Change-Id: If29d2ab2f86f263bdf43700426d86c873c30a001
Reviewed-on: https://go-review.googlesource.com/c/exp/+/589515
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Auto-Submit: Michael Knyszek <mknyszek@google.com>
Reviewed-by: Carlos Amedee <carlos@golang.org>

trace/event.go

diff --git a/trace/event.go b/trace/event.go
index 6fb6f60..a3093fd 100644
--- a/trace/event.go
+++ b/trace/event.go
@@ -667,11 +667,11 @@
 		panic("Experimental called on non-Experimental event")
 	}
 	spec := go122.Specs()[e.base.typ]
-	argNames := spec.Args[1:]
+	argNames := spec.Args[1:] // Skip timestamp; already handled.
 	return ExperimentalEvent{
 		Name:     spec.Name,
-		ArgNames: argNames, // Skip timestamp; already handled.
-		Args:     e.base.args[1 : 1+len(argNames)],
+		ArgNames: argNames,
+		Args:     e.base.args[:len(argNames)],
 		Data:     e.table.expData[spec.Experiment],
 	}
 }