Put 'empty' comments inside ignored catch blocks

Follow codacy rule against empty blocks.

apitest/src/main/java/bisq/apitest/Scaffold.java

@@ -188,6 +188,7 @@ public class Scaffold {
                             firstException = Optional.of(p.getShutdownExceptions().get(0));
                     }
                 } catch (InterruptedException ignored) {
+                    // empty
                 }
             }
         }

apitest/src/main/java/bisq/apitest/linux/BitcoinDaemon.java

@@ -109,6 +109,7 @@ public class BitcoinDaemon extends AbstractLinuxProcess implements LinuxProcess
 
             log.info("Stopped");
         } catch (InterruptedException ignored) {
+            // empty
         } catch (IOException e) {
             this.shutdownExceptions.add(new IllegalStateException("Error shutting down bitcoind.", e));
         }

apitest/src/main/java/bisq/apitest/linux/ThreadedStreamHandler.java

@@ -80,6 +80,7 @@ class ThreadedStreamHandler extends Thread {
         try {
             Thread.sleep(millis);
         } catch (InterruptedException ignored) {
+            // empty
         }
     }
 

apitest/src/test/java/bisq/apitest/ApiTestCase.java

@@ -88,6 +88,7 @@ public class ApiTestCase {
         try {
             MILLISECONDS.sleep(ms);
         } catch (InterruptedException ignored) {
+            // empty
         }
     }
 }