Use Version.compareMajor instead of using equals operator (#1876)

This test fails due to equality check of majors between OpenSearch Version 1.x and LegacyESVersion 7.x. They should be equivalent but in this case the check fails and LegacyVersion.v6.8.x is chosen which was removed in 52508d5.

This change fixes the comparison logic by using `Version.compareMajor` method instead.

Signed-off-by: Rabi Panda <adnapibar@gmail.com>

server/src/test/java/org/opensearch/cluster/coordination/JoinTaskExecutorTests.java

@@ -122,7 +122,7 @@ public class JoinTaskExecutorTests extends OpenSearchTestCase {
             expectThrows(IllegalStateException.class, () -> JoinTaskExecutor.ensureMajorVersionBarrier(oldMajor, minNodeVersion));
         }
 
-        final Version minGoodVersion = maxNodeVersion.major == minNodeVersion.major ?
+        final Version minGoodVersion = maxNodeVersion.compareMajor(minNodeVersion) == 0 ?
         // we have to stick with the same major
             minNodeVersion : maxNodeVersion.minimumCompatibilityVersion();
         final Version justGood = randomVersionBetween(random(), minGoodVersion, maxCompatibleVersion(minNodeVersion));