Fix after PR comments

1. Don't set IV onECB
2. Fix style issues
3. reduce number of tests
diff --git a/library/cipher_wrap.c b/library/cipher_wrap.c
index dc76af8..dbc5d3f 100644
--- a/library/cipher_wrap.c
+++ b/library/cipher_wrap.c
@@ -204,7 +204,7 @@
     MBEDTLS_MODE_ECB,
     128,
     "AES-128-ECB",
-    16,
+    0,
     0,
     16,
     &aes_info
@@ -215,7 +215,7 @@
     MBEDTLS_MODE_ECB,
     192,
     "AES-192-ECB",
-    16,
+    0,
     0,
     16,
     &aes_info
@@ -226,7 +226,7 @@
     MBEDTLS_MODE_ECB,
     256,
     "AES-256-ECB",
-    16,
+    0,
     0,
     16,
     &aes_info