testing: add Name method to *T and *B

Fixes #17231

Change-Id: I0d6007ab504f2277cb6affc9e2050157a6ad4d5e
Reviewed-on: https://go-review.googlesource.com/29970
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
Reviewed-by: Minux Ma <minux@golang.org>
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>

src/testing/testing.go

@@ -372,6 +372,7 @@ type TB interface {
 	Fatalf(format string, args ...interface{})
 	Log(args ...interface{})
 	Logf(format string, args ...interface{})
+	Name() string
 	Skip(args ...interface{})
 	SkipNow()
 	Skipf(format string, args ...interface{})
@@ -404,6 +405,11 @@ type T struct {
 
 func (c *common) private() {}
 
+// Name returns the name of the running test or benchmark.
+func (c *common) Name() string {
+	return c.name
+}
+
 // Fail marks the function as having failed but continues execution.
 func (c *common) Fail() {
 	if c.parent != nil {