IgnoreAllErrorHandler should use doPrivileged when it reads system properties

If security manager is enabled, but "org.jcp.xml.dsig.secureValidation" property is off, the impl tries to read the following system properties:

    com.sun.org.apache.xml.internal.security.test.warn.on.exceptions
    com.sun.org.apache.xml.internal.security.test.throw.exceptions

, and if appropriate property permissions are not granted, it fails with ExceptionInInitializerError

java.lang.ExceptionInInitializerError
    at com.sun.org.apache.xml.internal.security.signature.XMLSignatureInput.convertToNodes(XMLSignatureInput.java:568)
    ...
Caused by: java.security.AccessControlException: access denied ("java.util.PropertyPermission" "com.sun.org.apache.xml.internal.security.test.warn.on.exceptions" "read")
    at java.security.AccessControlContext.checkPermission(AccessControlContext.java:468)
    at java.security.AccessController.checkPermission(AccessController.java:894)
    at java.lang.SecurityManager.checkPermission(SecurityManager.java:541)
    at java.lang.SecurityManager.checkPropertyAccess(SecurityManager.java:1285)
    at java.lang.System.getProperty(System.java:744)
    at com.sun.org.apache.xml.internal.security.utils.IgnoreAllErrorHandler.<clinit>(IgnoreAllErrorHandler.java:43)
    ... 19 more

Please see http://hg.openjdk.java.net/jdk9/dev/jdk/file/97a1facbcaaa/src/java.xml.crypto/share/classes/com/sun/org/apache/xml/internal/security/utils/IgnoreAllErrorHandler.java

...
    /** Field throwExceptions */
    private static final boolean warnOnExceptions =
        System.getProperty("com.sun.org.apache.xml.internal.security.test.warn.on.exceptions", "false").equals("true");

    /** Field throwExceptions */
    private static final boolean throwExceptions =
        System.getProperty("com.sun.org.apache.xml.internal.security.test.throw.exceptions", "false").equals("true");
...

I think it is not really necessary to check access for these properties. IgnoreAllErrorHandler should read them inside doPrivileged() method.