TESTS: Remove the READ6 0-blocks test.

Since you can not request a read for 0 blocks with READ6
this test makes no sense.
(transfer length ==0  means 256 blocks for READ6)

test-tool/iscsi-test-cu.h

@@ -104,7 +104,6 @@ void test_prout_reserve_ownership_wear(void);
 
 void test_read6_simple(void);
 void test_read6_beyond_eol(void);
-void test_read6_0blocks(void);
 void test_read6_rdprotect(void);
 void test_read6_flags(void);