test: use testlib in a few more cases
        Introduce a new skip cmd.

R=golang-dev, bradfitz, iant, iant
CC=golang-dev
https://golang.org/cl/5868048
diff --git a/test/cmplxdivide.c b/test/cmplxdivide.c
index b340f04..12dc4f1 100644
--- a/test/cmplxdivide.c
+++ b/test/cmplxdivide.c
@@ -51,6 +51,7 @@
 	int i, j, k, l;
 	double complex n, d, q;
 	
+	printf("// skip\n");
 	printf("// # generated by cmplxdivide.c\n");
 	printf("\n");
 	printf("package main\n");