Fix missing non_qualified fields for gendered emoji

Some fully-qualified emoji have multiple unqualified forms in
emoji-test.txt:

    1F3F3 FE0F 200D 26A7 FE0F                              ; fully-qualified     # 🏳️‍⚧️ E13.0 transgender flag
    1F3F3 200D 26A7 FE0F                                   ; unqualified         # 🏳‍⚧️ E13.0 transgender flag
    1F3F3 FE0F 200D 26A7                                   ; unqualified         # 🏳️‍⚧ E13.0 transgender flag
    1F3F3 200D 26A7                                        ; unqualified         # 🏳‍⚧ E13.0 transgender flag

We need to build `$qualified_map` based on the first (fully-qualified)
row for each emoji, not the last one that has an FE0F.

Fixes #233.

Signed-off-by: Anders Kaseorg <andersk@mit.edu>

build/build_map.php

@@ -97,7 +97,9 @@
 			$p++;
 
 			$cp_nq = str_replace('-fe0f', '', $cp);
-			if ($cp != $cp_nq) $qualified_map[$cp_nq] = $cp;
+			if ($cp != $cp_nq && !isset($qualified_map[$cp_nq])){
+				$qualified_map[$cp_nq] = $cp;
+			}
 		}
 	}