jdk/sun/security/tools/jarsigner/compatibility/SignTwice.java slow on Windows

SignTwice test takes a few minutes to complete on Windows; on other OSes it usually finishes under a minute.

The test repeatedly runs jarsigner with different parameters; it also adds -J-Djava.security.egd=file:/dev/./urandom to the command line. That parameter adds a few seconds to the tool startup time. Removing that parameter or changing its value to file:/dev/urandom (without the dot in the middle) allows the test to complete under a minute, similar to other platforms.