Rename RecursiveMergerTest and ResolveMergerTest to reduce confusion

The class names imply that RecursiveMergerTest tests the RecursiveMerger
and ResolveMergerTest tests the ResolveMerger.

In fact, both of them include coverage of both strategies; the difference
is that RecursiveMergerTest is only testing criss-cross merges.

The tests cannot be combined into a single class because the criss-cross
test methods have additional data points.

Instead, rename the classes to more meaningful names.

Change-Id: I7ca8a03a3b7e351e2d4fcaca3b3186c098a3ca66
Signed-off-by: David Pursehouse <david.pursehouse@gmail.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/CrissCrossMergeTest.java

@@ -83,7 +83,7 @@ import org.junit.experimental.theories.Theory;
 import org.junit.runner.RunWith;
 
 @RunWith(Theories.class)
-public class RecursiveMergerTest extends RepositoryTestCase {
+public class CrissCrossMergeTest extends RepositoryTestCase {
 	static int counter = 0;
 
 	@DataPoints

org.eclipse.jgit.test/tst/org/eclipse/jgit/merge/MergerTest.java

@@ -97,7 +97,7 @@ import org.junit.experimental.theories.Theory;
 import org.junit.runner.RunWith;
 
 @RunWith(Theories.class)
-public class ResolveMergerTest extends RepositoryTestCase {
+public class MergerTest extends RepositoryTestCase {
 
 	@DataPoints
 	public static MergeStrategy[] strategiesUnderTest = new MergeStrategy[] {