cmd/go: rename TestModLegacy* to TestLegacyMod*

This preserves the property that -run=^TestMod selects exactly those in mod_test.go.

Change-Id: Ib186b4f56d598669f08440befe6d2baedc947298
Reviewed-on: https://go-review.googlesource.com/123360
Reviewed-by: Bryan C. Mills <bcmills@google.com>
diff --git a/vendor/cmd/go/vendor_test.go b/vendor/cmd/go/vendor_test.go
index c2b3d6a..6a68b69 100644
--- a/vendor/cmd/go/vendor_test.go
+++ b/vendor/cmd/go/vendor_test.go
@@ -332,7 +332,7 @@
 
 // Module legacy support does path rewriting very similar to vendoring.
 
-func TestModLegacy(t *testing.T) {
+func TestLegacyMod(t *testing.T) {
 	tg := testgo(t)
 	defer tg.cleanup()
 	tg.setenv("GOPATH", filepath.Join(tg.pwd(), "testdata/modlegacy"))
@@ -347,7 +347,7 @@
 	tg.run("build", "old/p1", "new/p1")
 }
 
-func TestModLegacyGet(t *testing.T) {
+func TestLegacyModGet(t *testing.T) {
 	testenv.MustHaveExternalNetwork(t)
 
 	tg := testgo(t)