Improve handling of mismatching /BaseFont and /FontName entries for non-embedded fonts (issue 7454)

This patch is the result of me going through some old issues regarding non-embedded Wingdings support.

There's a few different things wrong in the referenced PDF document:
 - The /BaseFont and /FontName entries don't agree on the name of the fonts, with one font using `/BaseFont /Wingdings-Regular` and `/FontName /wg09np` which obviously makes no sense.
   To address this we'll compare the font-names against our lists of known ones and ignore /FontName entries that don't make sense iff the /BaseFont entry is a known font-name.
 - The non-embedded Wingdings font also set an incorrect /Encoding, in this case /MacRomanEncoding, which should have been fixed by PR 16465. However this doesn't work since the font has *bogus* font-flags, that fail to categorize the font as Symbolic.
   To address this we'll also compare the font-name against the list of known symbol fonts.

test/pdfs/.gitignore

@@ -490,6 +490,7 @@
 !issue11656.pdf
 !annotation-fileattachment.pdf
 !annotation-text-widget.pdf
+!issue7454.pdf
 !issue15443.pdf
 !annotation-choice-widget.pdf
 !issue10900.pdf

test/test_manifest.json

@@ -5042,6 +5042,12 @@
       "link": true,
       "type": "load"
     },
+    {  "id": "issue7454",
+       "file": "pdfs/issue7454.pdf",
+       "md5": "45889bf6a9d3e2eccd01dc48668b21e5",
+       "rounds": 1,
+       "type": "eq"
+    },
     { "id": "bigboundingbox",
       "file": "pdfs/bigboundingbox.pdf",
       "md5": "e5c5e2cb80826d6ebf535413865270cd",