Edge: correct URL to local resource in tests eclipse-platform#1670

The URL used for the `test_setUrl_Local()` browser test case currently
only consists of a file path when provided via the `PLUGIN_PATH`
environment variable, e.g., during I-Build test execution.
Edge does, however, require a valid URL with an according protocol
prefix. Currently, the drive prefix of the file path is erroneously
treated as the protocol.

This change properly converts the path to a URL.

Fixes eclipse-platform#1670

Author: HeikoKlare

tests/org.eclipse.swt.tests/JUnit Tests/org/eclipse/swt/tests/junit/Test_org_eclipse_swt_browser_Browser.java

@@ -762,7 +762,7 @@ private String getValidUrl() {
 	testLogAppend("PLUGIN_PATH: " + pluginPath);
 	// When test is run via Ant, URL needs to be acquired differently. In that case the PLUGIN_PATH property is set and used.
 	if (pluginPath != null) {
-		return pluginPath + "/data/testWebsiteWithTitle.html";
+		return Path.of(pluginPath, "data/testWebsiteWithTitle.html").toUri().toString();
 	} else {
 		// used when ran from Eclipse gui.
 		return Test_org_eclipse_swt_browser_Browser.class.getClassLoader().getResource("testWebsiteWithTitle.html").toString();