Replace Device::getDPI() usage in SWT Snippets/Test

Following are the places that needed to be replaced:

```
org.eclipse.swt.snippets.Snippet367.main(String[])
org.eclipse.swt.examples.imageanalyzer.ImageAnalyzer.menuPrint()
org.eclipse.swt.snippets.Snippet361.performPrintAction(Display, Shell)
org.eclipse.swt.tests.junit.Test_org_eclipse_swt_widgets_Display.test_getDPI()
```