Streamline Logging Across TestNG

Closes testng-team#2646

We now use sl4j apis for our logging.
Internally TestNG makes use of SimpleLogger 
(Slf4j-simple) bindings for logging purposes.

CHANGES.txt

@@ -1,4 +1,5 @@
 Current
+Fixed: GITHUB-2646: Streamline Logging Across TestNG (Krishnan Mahadevan)
 Fixed: GITHUB-2664: Order for DependsOnGroups has changed after TestNg 7.4.0 (Krishnan Mahadevan)
 Fixed: GITHUB-2501: TestNG 7.4.0 throws an exception "sun.net.www.protocol.file.FileURLConnection cannot be cast to java.net.HttpURLConnection" when xml file contain "ENTITY SYSTEM" grammer (Krishnan Mahadevan)
 Fixed: GITHUB-2693: TestNG ignores 'dataproviderthreadcount' CLA (Krishnan Mahadevan)

testng-ant/src/test/java/test/ant/AntTest.java

@@ -2,22 +2,20 @@
 
 import static org.assertj.core.api.Assertions.assertThat;
 
-import java.io.File;
-import java.io.IOException;
+import java.util.regex.Pattern;
 import org.apache.tools.ant.BuildFileRule;
-import org.apache.tools.ant.FileUtilities;
 import org.testng.annotations.Test;
 
 public class AntTest {
 
   private final BuildFileRule rule = new BuildFileRule();
 
   @Test
-  public void testSimple() throws IOException {
+  public void testSimple() {
     rule.configureProject("src/test/resources/ant/build-simple.xml");
     rule.executeTarget("testng");
-    File expected = rule.getProject().resolveFile("expected/ant-simple.test");
-    assertThat(rule.getLog()).isEqualToIgnoringNewLines(FileUtilities.getFileContents(expected));
+    String expectedText = "Total tests run: 1, Passes: 1, Failures: 0, Skips: 0";
+    assertThat(rule.getLog()).containsPattern(Pattern.compile(expectedText));
   }
 
   @Test