Check that Type1C fonts does not actually contain OpenType font files (issue 7598)

This patch is yet another instalment in the (never ending) series of patches for PDF files that specify completely incorrect Type/Subtype for its fonts. In this case Type1/Type1C, when in fact OpenType would have been correct.

Fixes 7598.

test/pdfs/.gitignore

@@ -35,6 +35,7 @@
 !issue7439.pdf
 !issue7446.pdf
 !issue7492.pdf
+!issue7598.pdf
 !filled-background.pdf
 !ArabicCIDTrueType.pdf
 !ThuluthFeatures.pdf

test/test_manifest.json

@@ -1795,6 +1795,13 @@
        "link": false,
        "type": "eq"
     },
+    {  "id": "issue7598",
+       "file": "pdfs/issue7598.pdf",
+       "md5": "c5bc5a779bfcb4b234f853231b56cf60",
+       "rounds": 1,
+       "link": false,
+       "type": "eq"
+    },
     {  "id": "issue7439",
        "file": "pdfs/issue7439.pdf",
        "md5": "56682657990a894c66db26560d3039d7",