Don't map glyphs to Unicode position 0x0E33, i.e. Thai character SARA AM (bug1046314)

*A similar approach as in PR 5705.*

Fixes https://bugzilla.mozilla.org/show_bug.cgi?id=1046314.

According to https://dxr.mozilla.org/mozilla-central/source/gfx/harfbuzz/src/hb-ot-shape-complex-thai.cc#270-365, `0x0E33` is treated as a special case (by the font shaping code in Firefox). Hence it seems reasonable to skip it when adjusting the font mapping.

test/pdfs/.gitignore

@@ -86,6 +86,7 @@
 !bug866395.pdf
 !bug1027533.pdf
 !bug1028735.pdf
+!bug1046314.pdf
 !bug1065245.pdf
 !basicapi.pdf
 !mixedfonts.pdf

test/test_manifest.json

@@ -557,6 +557,13 @@
        "rounds": 1,
        "type": "load"
     },
+    {  "id": "bug1046314",
+       "file": "pdfs/bug1046314.pdf",
+       "md5": "fc658439f44cd2dd27c8bee7e7a8344e",
+       "rounds": 1,
+       "link": false,
+       "type": "eq"
+    },
     {  "id": "hudsonsurvey",
        "file": "pdfs/hudsonsurvey.pdf",
        "md5": "bf0e6576a7b6c2fe7485bce1b78e006f",