internal/trace: rename "oldtrace" to trace v1

This is part of a refactoring to better distinguish trace wire format
versions. Even though details may change between Go versions and they
might be backwards-incompatible, the trace format still broadly has two
wire formats: v1 and v2.

A follow-up change will rename go122 to v2 to make this more consistent.

Change-Id: If4fe1c82d8aeabc8baa05f525e08a9e7d469a5c7
Reviewed-on: https://go-review.googlesource.com/c/go/+/644217
Auto-Submit: Michael Knyszek <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>
Reviewed-by: Michael Pratt <[email protected]>

Author: mknyszek

src/go/build/deps_test.go

@@ -711,9 +711,9 @@ var depsRules = `
 	< internal/trace/raw;
 
 	FMT, internal/trace/event, internal/trace/version, io, sort, encoding/binary
-	< internal/trace/internal/oldtrace;
+	< internal/trace/internal/tracev1;
 
-	FMT, encoding/binary, internal/trace/version, internal/trace/internal/oldtrace, container/heap, math/rand
+	FMT, encoding/binary, internal/trace/version, internal/trace/internal/tracev1, container/heap, math/rand
 	< internal/trace;
 
 	regexp, internal/trace, internal/trace/raw, internal/txtar