go/build: add back deps for runtime/pprof/internal/gzip0

These were accidentally removed by a rollback cl: golang.org/cl/32441

Change-Id: I0cfa8b3397be324dabfb8f33b6548a03c10571eb
Reviewed-on: https://go-review.googlesource.com/32334Reviewed-by: Alan Donovan <adonovan@google.com>

src/go/build/deps_test.go

@@ -173,6 +173,7 @@ var pkgDeps = map[string][]string{
 	"regexp":                       {"L2", "regexp/syntax"},
 	"regexp/syntax":                {"L2"},
 	"runtime/debug":                {"L2", "fmt", "io/ioutil", "os", "time"},
+	"runtime/pprof/internal/gzip0": {"L2"},
 	"runtime/pprof":                {"L2", "fmt", "os", "text/tabwriter"},
 	"runtime/trace":                {"L0"},
 	"text/tabwriter":               {"L2"},