adding more unit tests and upgrading jacoco (opensearch-project#4057)

Signed-off-by: Dhrubo Saha <dhrubo@amazon.com>

Author: dhrubo-os

build.gradle

@@ -80,7 +80,7 @@ allprojects {
     }
 
     plugins.withId('jacoco') {
-        jacoco.toolVersion = '0.8.12'
+        jacoco.toolVersion = '0.8.13'
     }
 
     project.getExtensions().getExtraProperties().set("versions", VersionProperties.getVersions());