fix compilation error for non-english windows (like cjk)

add /utf-8 switch for msvc build. source code has several utf-8 characters
fix C2001 error. escape non-printable ascii code generated by embed_test_data.go
fix C4819 warning. add u8 keyword on utf-8 string literal (ripemd_test.cc)

Change-Id: I8c04dc7f0359e6ee27efada066863826d263d5cd
Reviewed-on: https://boringssl-review.googlesource.com/26484
Reviewed-by: David Benjamin <davidben@google.com>
Commit-Queue: David Benjamin <davidben@google.com>
CQ-Verified: CQ bot account: commit-bot@chromium.org <commit-bot@chromium.org>
diff --git a/util/embed_test_data.go b/util/embed_test_data.go
index ffc446b..a083848 100644
--- a/util/embed_test_data.go
+++ b/util/embed_test_data.go
@@ -21,7 +21,6 @@
 	"fmt"
 	"io/ioutil"
 	"os"
-	"unicode"
 )
 
 func quote(in []byte) string {
@@ -46,7 +45,8 @@
 		case '"':
 			buf.WriteString(`\"`)
 		default:
-			if rune(b) > 127 || unicode.IsPrint(rune(b)) {
+			// printable ascii code [32, 126]
+			if 32 <= b && b <= 126 {
 				buf.WriteByte(b)
 			} else {
 				fmt.Fprintf(&buf, "\\x%02x", b)