Fix FileSystemAccessTest::testFileActions() flakiness

Always add " > /dev/null 2>&1" infix so that the
output of e.g. "rm" command, when failed, is redirected
to dev/null.

Enclose the input data in runInShell() with quotation
marks and escape all the characters in passed data
accordingly. Pass the "-e" option to echo in order to
turn on the escaping mode.

Add a new test for testCreateRemoteFile().

Change-Id: I7db07b57035242279cac7dd77a80ac6dd05bfb1f
Reviewed-by: Christian Stenger <christian.stenger@qt.io>
Reviewed-by: hjk <hjk@qt.io>

src/plugins/remotelinux/filesystemaccess_test.h

@@ -45,12 +45,15 @@ class FileSystemAccessTest : public QObject
 
 private slots:
     void initTestCase();
-    void cleanupTestCase();
 
-    void testDirStatuses();
+    void testCreateRemoteFile_data();
+    void testCreateRemoteFile();
+    void testDirStatus();
     void testBytesAvailable();
     void testFileActions();
 
+    void cleanupTestCase();
+
 private:
     TestLinuxDeviceFactory m_testLinuxDeviceFactory;
     bool m_skippedAtWhole = false;