runtime/race: update two stale references

Fixes #13550

Change-Id: I407daad8b94f6773d7949ba27981d26cbfd2cdf4
Reviewed-on: https://go-review.googlesource.com/17682Reviewed-by: Russ Cox <rsc@golang.org>

src/runtime/race/race.go

@@ -9,7 +9,7 @@ package race
 // This file merely ensures that we link in runtime/cgo in race build,
 // this is turn ensures that runtime uses pthread_create to create threads.
 // The prebuilt race runtime lives in race_GOOS_GOARCH.syso.
-// Calls to the runtime are done directly from src/runtime/race.c.
+// Calls to the runtime are done directly from src/runtime/race.go.
 
 // void __race_unused_func(void);
 import "C"

src/runtime/race/testdata/select_test.go

@@ -19,7 +19,7 @@ func TestNoRaceSelect1(t *testing.T) {
 		x = 1
 		// At least two channels are needed because
 		// otherwise the compiler optimizes select out.
-		// See comment in runtime/chan.c:^selectgo.
+		// See comment in runtime/select.go:^func selectgoImpl.
 		select {
 		case c <- true:
 		case c1 <- true: