[dev.boringcrypto] runtime/race: move TestRaceIssue5567 from sha1 to crc32

If we substitute a SHA1 implementation where the entirety of the
reading of the buffer is done in assembly (or C called from cgo),
then the race detector cannot observe the race.

Change to crc32 with a fake polynomial, in the hope that it will
always be handled by Go code, not optimized assembly or cgo calls.

Change-Id: I34e90b14ede6bc220ef686f6aef16b8e464b5cde
Reviewed-on: https://go-review.googlesource.com/56510
Run-TryBot: Russ Cox <rsc@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/runtime/race/testdata/mop_test.go

@@ -6,9 +6,9 @@ package race_test
 
 import (
 	"bytes"
-	"crypto/sha1"
 	"errors"
 	"fmt"
+	"hash/crc32"
 	"io"
 	"os"
 	"runtime"
@@ -1904,7 +1904,7 @@ func TestRaceIssue5567(t *testing.T) {
 			err = nil
 		}
 	}()
-	h := sha1.New()
+	h := crc32.New(crc32.MakeTable(0x12345678))
 	for b := range in {
 		h.Write(b)
 	}