Only special-case OpenType fonts with CFF data if it's both a composite (i.e. Type0) font and also has a non-default CID to GID map (issue 8480)

*As mentioned the last time that I touched this particular part of the font code, I'm sincerely hope that this doesn't cause any regressions!*

However, the patch passes all tests added in PRs 5770, 6270, and 7904 (and obviously all other tests as well). Furthermore, I've manually checked all the issues/bugs referenced in those PRs without finding any issues.

Fixes 8480.

test/pdfs/.gitignore

@@ -52,6 +52,7 @@
 !issue8125.pdf
 !issue8372.pdf
 !issue8424.pdf
+!issue8480.pdf
 !bad-PageLabels.pdf
 !filled-background.pdf
 !ArabicCIDTrueType.pdf

test/test_manifest.json

@@ -1149,6 +1149,13 @@
        "link": false,
        "type": "eq"
     },
+    {  "id": "issue8480",
+       "file": "pdfs/issue8480.pdf",
+       "md5": "769bc07bf8041d95667f2d32aaf75665",
+       "rounds": 1,
+       "link": false,
+       "type": "eq"
+    },
     {  "id": "tutorial",
        "file": "pdfs/tutorial.pdf",
        "md5": "6e122f618c27f3aa9a689423e3be6b8d",