More updater fixage

Preserve --dir parameter after updating
Allow more than one copy of a command line parameter in MultiMC
Linux runner script no longer changes current directory, which allows '--dir .'
Fixed unit tests, removed the obsolete one (for some legacy updater command line params that were also removed)
[fixes 63127704]

tests/TestUtil.h

@@ -39,7 +39,7 @@ int main(int argc, char *argv[]) \
 { \
 	char *argv_[] = { argv[0] _MMC_EXTRA_ARGV }; \
 	int argc_ = 1 + _MMC_EXTRA_ARGC; \
-	MultiMC app(argc_, argv_/*, QDir::temp().absoluteFilePath("MultiMC_Test")*/); \
+	MultiMC app(argc_, argv_, true); \
 	app.setAttribute(Qt::AA_Use96Dpi, true); \
 	TestObject tc; \
 	return QTest::qExec(&tc, argc, argv); \

tests/tst_DownloadUpdateTask.cpp

@@ -254,7 +254,7 @@ slots:
 		pathOrig = path = "MultiMC.app/Foo/Bar/Baz";
 		qDebug() << "Proper OSX path: " << path;
 		result = DownloadUpdateTask::fixPathForOSX(path);
-		QCOMPARE(path, QString("../../Foo/Bar/Baz"));
+		QCOMPARE(path, QString("Foo/Bar/Baz"));
 		QCOMPARE(result, true);
 
 		// Bad OSX path