testing: consider a test failed after race errors

Fixes #19851.

Change-Id: I5ee9533406542be7d5418df154f6134139e75892
Reviewed-on: https://go-review.googlesource.com/39890
Run-TryBot: Caleb Spare <cespare@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Russ Cox <rsc@golang.org>

src/runtime/race/output_test.go

@@ -181,10 +181,12 @@ func TestFail(t *testing.T) {
 	}()
 	x = 43
 	<-done
+	t.Log(t.Failed())
 }
 `, `
 ==================
 --- FAIL: TestFail \(0...s\)
+.*main_test.go:13: true
 .*testing.go:.*: race detected during execution of test
 FAIL`},
 

src/testing/testing.go

@@ -450,8 +450,9 @@ func (c *common) Fail() {
 // Failed reports whether the function has failed.
 func (c *common) Failed() bool {
 	c.mu.RLock()
-	defer c.mu.RUnlock()
-	return c.failed
+	failed := c.failed
+	c.mu.RUnlock()
+	return failed || c.raceErrors+race.Errors() > 0
 }
 
 // FailNow marks the function as having failed and stops its execution.