net/http: maybe fix TestLinuxSendfile on mips64

Updates #18008

Change-Id: I8fde0d71d15b416db4d262f6db8ef32a209a192f
Reviewed-on: https://go-review.googlesource.com/33426Reviewed-by: Ian Lance Taylor <iant@golang.org>

src/net/http/fs_test.go

@@ -1086,10 +1086,14 @@ func TestLinuxSendfile(t *testing.T) {
 
 	syscalls := "sendfile,sendfile64"
 	switch runtime.GOARCH {
-	case "mips64", "mips64le", "s390x":
+	case "mips64le", "s390x":
 		// strace on the above platforms doesn't support sendfile64
 		// and will error out if we specify that with `-e trace='.
 		syscalls = "sendfile"
+	case "mips64":
+		// TODO: minimize this set once golang.org/issue/18008
+		// is understood.
+		syscalls = "network,file"
 	}
 
 	var buf bytes.Buffer