Fix symlinks being replaced with files on save

Fixes arduino#5478

Author: facchinm

app/src/processing/app/Editor.java

@@ -2228,6 +2228,7 @@ private void resumeOrCloseSerialMonitor() {
             serialMonitor.close();
             handleSerial();
           } else {
+            Thread.sleep(200);
             serialMonitor.resume(boardPort);
           }
         }

arduino-core/src/cc/arduino/packages/uploaders/SerialUploader.java

@@ -157,7 +157,7 @@ public boolean uploadUsingPreferences(File sourcePath, String buildPath, String
     	  Thread.sleep(250);
         }
       } catch (SerialException e) {
-        throw new RunnerException(e);
+        throw new RunnerException(e.getMessage());
       } catch (InterruptedException e) {
         throw new RunnerException(e.getMessage());
       } finally {

arduino-core/src/processing/app/BaseNoGui.java

@@ -33,6 +33,8 @@
 import java.util.*;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import java.nio.file.Files;
+import java.nio.file.Path;
 
 import cc.arduino.packages.BoardPort;
 
@@ -1058,6 +1060,10 @@ static public void saveFile(String str, File file) throws IOException {
     File temp = File.createTempFile(file.getName(), null, file.getParentFile());
     PApplet.saveStrings(temp, new String[] { str });
     if (file.exists()) {
+      boolean isSymbolicLink = Files.isSymbolicLink(file.toPath());
+      if (isSymbolicLink) {
+        file = file.toPath().toRealPath().toFile().getAbsoluteFile();
+      }
       boolean result = file.delete();
       if (!result) {
         throw new IOException(