tests: avoid assertEquals on same instance

[SelfAssertion] You are passing identical arguments to the
assertEquals method, so this assertion always passes. THIS IS LIKELY A
BUG!

See https://errorprone.info/bugpattern/SelfAssertion

Replacing assertEquals(x, x) with assertTrue(x.equals(x)).

Change-Id: I4fd631adbee35e68ab59d92a2c67d5e3c821c537

org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditListTest.java

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditListTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditListTest.java
index f657bab..a2c20aa 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditListTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditListTest.java
@@ -28,7 +28,7 @@ public void testEmpty() {
 		assertTrue(l.isEmpty());
 		assertEquals("EditList[]", l.toString());
 
-		assertEquals(l, l);
+		assertTrue(l.equals(l));
 		assertEquals(new EditList(), l);
 		assertFalse(l.equals(""));
 		assertEquals(l.hashCode(), new EditList().hashCode());
@@ -44,7 +44,7 @@ public void testAddOne() {
 		assertSame(e, l.get(0));
 		assertSame(e, l.iterator().next());
 
-		assertEquals(l, l);
+		assertTrue(l.equals(l));
 		assertFalse(l.equals(new EditList()));
 
 		final EditList l2 = new EditList();
@@ -69,7 +69,7 @@ public void testAddTwo() {
 		assertSame(e1, i.next());
 		assertSame(e2, i.next());
 
-		assertEquals(l, l);
+		assertTrue(l.equals(l));
 		assertFalse(l.equals(new EditList()));
 
 		final EditList l2 = new EditList();

org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditTest.java

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditTest.java
index 8ab9bb1..86c6d77 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/diff/EditTest.java
@@ -98,7 +98,7 @@ public void testEquals1() {
 		final Edit e1 = new Edit(1, 2, 3, 4);
 		final Edit e2 = new Edit(1, 2, 3, 4);
 
-		assertEquals(e1, e1);
+		assertTrue(e1.equals(e1));
 		assertEquals(e2, e1);
 		assertEquals(e1, e2);
 		assertEquals(e1.hashCode(), e2.hashCode());

org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/BasicRuleTest.java

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/BasicRuleTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/BasicRuleTest.java
index 6112952..6983eaa 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/BasicRuleTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/ignore/BasicRuleTest.java
@@ -31,7 +31,7 @@ public void test() {
 		assertFalse(rule1.getNegation());
 		assertTrue(rule3.getNegation());
 		assertNotEquals(rule1, null);
-		assertEquals(rule1, rule1);
+		assertTrue(rule1.equals(rule1));
 		assertEquals(rule1, rule2);
 		assertNotEquals(rule1, rule3);
 		assertNotEquals(rule1, rule4);

org.eclipse.jgit.test/tst/org/eclipse/jgit/util/RefMapTest.java

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/RefMapTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/RefMapTest.java
index a8077fd..0c9cb2d 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/RefMapTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/util/RefMapTest.java
@@ -423,7 +423,7 @@ public void testEntryType() {
 		Map.Entry<String, Ref> ent_b = itr.next();
 
 		assertEquals(ent_a.hashCode(), "A".hashCode());
-		assertEquals(ent_a, ent_a);
+		assertTrue(ent_a.equals(ent_a));
 		assertFalse(ent_a.equals(ent_b));
 
 		assertEquals(a.toString(), ent_a.toString());