[JENKINS-39179] [JENKINS-36088] Always use NIO to create and detect symbolic links and Windows junctions (#3133)

* Always use NIO to detect symlinks

* Make assertion failure message consistent

* Catch NoSuchFileException to keep tests passing

* Make method name more specific and simlify assumption

* Remove obsolete comment and reword the main comment in isSymlink

* Deprecate Kernel32Util#isJunctionOrSymlink

* Use assumptions for junction creation and add messages to assumptions

* Replace deprecated code with recommended alternative

* Add comment explaining call to DosFileAttributes#isOther

* Do not fall back to native code when creating symlinks

* Log FileSystemExceptions when creating symbolic links

* Catch InvalidPathException and rethrow as IOException

* Deprecate Kernel32Utils#createSymbolicLink and #getWin32FileAttributes

* Preserve original logging behavior on Windows and remove useless call to Util#displayIOException

In addition to cluttering the namespace, unused imports generate
compiler warnings, introducing noise and obscuring more important
compiler warnings.  This change removes them.

JNAerator ( https://code.google.com/p/jnaerator/ ) was helpful
for generating the Java code from the C struct.

Remove fields which are not part of struct _SHELLEXECUTEINFO.

Add getFieldOrder() methods to classes which extend com.sun.jna.Structure,
for compatibility with newer versions of JNA.  [JENKINS-24521]

[FIX JENKINS-22818] fix jenkins restart on Linux after plugin update if the java executable running Jenkins is started without its full path

The patch uses 'execvp' instead of 'execv' to lookup the java executable filename in the PATH if the specified filename does not contain a slash (/) character.
Regression introduced in 547d4ed8

The size is in wchar_t, not in bytes

Don't break Windows XP, fall back gracefully to no-op.

b5ed3199 already caught linkage errors but then unconditionally returned false from Util.isSymlink, which is wrong;
we want to fall back to the generic File.canonicalPath comparisons in this case.

Failure to load JNA should be handled graciously

JVM.

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@33219 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@24691 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@24373 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@24103 71c3de6d-444a-0410-be80-ed276b4c234a

git-svn-id: https://hudson.dev.java.net/svn/hudson/trunk/hudson/main@23469 71c3de6d-444a-0410-be80-ed276b4c234a