[svn-r18165] Purpose:

Add test cases for h5diff check-in (svn revision #18164).

Description:
    This test cases are for testing comparing through various link combinations
    relate to bugzilla report 1754.
    Also improved the test script to handle external link cases and
    simplified to use single line instead of double for each test cases. 

Tested on Jam

tools/h5diff/testfiles/h5diff_410.txt

@@ -0,0 +1,85 @@
+
+file1     file2
+---------------------------------------
+    x      x    /              
+    x      x    /softlink1_to_dset1
+    x      x    /softlink1_to_slink1
+    x      x    /softlink1_to_slink2
+    x      x    /softlink2_to_dset2
+    x      x    /softlink2_to_slink1
+    x      x    /softlink2_to_slink2
+    x      x    /softlink3_to_group1
+    x      x    /softlink3_to_slink1
+    x      x    /softlink3_to_slink2
+    x      x    /softlink4_to_group2
+    x      x    /softlink4_to_slink1
+    x      x    /softlink4_to_slink2
+    x      x    /target_dset1  
+    x      x    /target_dset2  
+    x      x    /target_group  
+    x      x    /target_group/dset
+    x      x    /target_group1 
+    x      x    /target_group2 
+
+group  : </> and </>
+0 differences found
+link   : </softlink1_to_dset1> and </softlink1_to_dset1>
+dataset: </target_dset1> and </target_dset1>
+0 differences found
+0 differences found
+link   : </softlink1_to_slink1> and </softlink1_to_slink1>
+dataset: <softlink1_to_dset1> and <softlink1_to_dset1>
+0 differences found
+0 differences found
+link   : </softlink1_to_slink2> and </softlink1_to_slink2>
+dataset: <softlink1_to_slink1> and <softlink1_to_slink1>
+0 differences found
+0 differences found
+link   : </softlink2_to_dset2> and </softlink2_to_dset2>
+dataset: </target_dset2> and </target_dset2>
+0 differences found
+0 differences found
+link   : </softlink2_to_slink1> and </softlink2_to_slink1>
+dataset: <softlink2_to_dset2> and <softlink2_to_dset2>
+0 differences found
+0 differences found
+link   : </softlink2_to_slink2> and </softlink2_to_slink2>
+dataset: <softlink2_to_slink1> and <softlink2_to_slink1>
+0 differences found
+0 differences found
+link   : </softlink3_to_group1> and </softlink3_to_group1>
+group  : <target_group1> and <target_group1>
+0 differences found
+0 differences found
+link   : </softlink3_to_slink1> and </softlink3_to_slink1>
+group  : <softlink3_to_group1> and <softlink3_to_group1>
+0 differences found
+0 differences found
+link   : </softlink3_to_slink2> and </softlink3_to_slink2>
+group  : <softlink3_to_slink1> and <softlink3_to_slink1>
+0 differences found
+0 differences found
+link   : </softlink4_to_group2> and </softlink4_to_group2>
+group  : <target_group2> and <target_group2>
+0 differences found
+0 differences found
+link   : </softlink4_to_slink1> and </softlink4_to_slink1>
+group  : <softlink4_to_group2> and <softlink4_to_group2>
+0 differences found
+0 differences found
+link   : </softlink4_to_slink2> and </softlink4_to_slink2>
+group  : <softlink4_to_slink1> and <softlink4_to_slink1>
+0 differences found
+0 differences found
+dataset: </target_dset1> and </target_dset1>
+0 differences found
+dataset: </target_dset2> and </target_dset2>
+0 differences found
+group  : </target_group> and </target_group>
+0 differences found
+dataset: </target_group/dset> and </target_group/dset>
+0 differences found
+group  : </target_group1> and </target_group1>
+0 differences found
+group  : </target_group2> and </target_group2>
+0 differences found