Disabling too-aggressive optimization in OptCmp8

Generates incorrect code for some 16-bit cases. See: #895

src/cc65/coptcmp.c

@@ -885,11 +885,16 @@ unsigned OptCmp8 (CodeSeg* S)
                 ++Changes;
             }
 
-            /* If we have made changes above, we may also remove the compare */
+            /* "If we have made changes above, we may also remove the compare."
-            if (JumpsChanged) {
+            **
-                CS_DelEntry (S, I);
+            ** Removing the compare was too aggressive. E.g. for 16-bit compares the compiler
-            }
+            ** may generate a branch to a second shared branch that still requires the flag
-
+            ** result of the first compare instruction.
+            **
+            **if (JumpsChanged) {
+            **    CS_DelEntry (S, I);
+            **}
+            */
         }
 
 NextEntry: