Fix Symbol fonts without font file but with Encoding dictionary (issue 5238)

src/core/fonts.js

@@ -2486,6 +2486,13 @@ var Font = (function FontClosure() {
           }
           this.toFontChar[charCode] = fontChar;
         }
+        for (charCode in properties.differences) {
+          fontChar = GlyphsUnicode[properties.differences[charCode]];
+          if (!fontChar) {
+            continue;
+          }
+          this.toFontChar[charCode] = fontChar;
+        }
       } else if (/Dingbats/i.test(fontName)) {
         var dingbats = Encodings.ZapfDingbatsEncoding;
         for (charCode in dingbats) {

test/pdfs/.gitignore

@@ -61,6 +61,7 @@
 !issue4668.pdf
 !issue5039.pdf
 !issue5070.pdf
+!issue5238.pdf
 !issue5244.pdf
 !gradientfill.pdf
 !bug903856.pdf

test/test_manifest.json

@@ -471,6 +471,13 @@
        "lastPage": 1,
        "type": "eq"
     },
+    {  "id": "issue5238",
+       "file": "pdfs/issue5238.pdf",
+       "md5": "6ddecda00893be1793de20a70c83a3c2",
+       "rounds": 1,
+       "link": false,
+       "type": "eq"
+    },
     {  "id": "txt2pdf",
        "file": "pdfs/txt2pdf.pdf",
        "md5": "02cefa0f5e8d96313bb05163b2f88c8c",