8295304: Runtime support improvements

Reviewed-by: rhalade, rriggs, bchristi
(cherry picked from commit 3656939a6a)

src/java.base/share/classes/java/lang/ProcessBuilder.java

@@ -1116,8 +1116,8 @@ public final class ProcessBuilder
 
         String dir = directory == null ? null : directory.toString();
 
-        for (int i = 1; i < cmdarray.length; i++) {
-            if (cmdarray[i].indexOf('\u0000') >= 0) {
+        for (String s : cmdarray) {
+            if (s.indexOf('\u0000') >= 0) {
                 throw new IOException("invalid null character in command");
             }
         }