Add unit tests for fgas_fontutils.cpp

These tests show some inconsistent behaviour with spaces in font names
that was noticed while working on other issues.

Change-Id: I0689275e5fa96dfd90ce4cadd1f998dac2ee5b32
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/87593
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/BUILD.gn b/BUILD.gn
index bdb5dae..717c8c3 100644
--- a/BUILD.gn
+++ b/BUILD.gn
@@ -445,6 +445,7 @@
         "fxbarcode:unittests",
         "xfa/fde:unittests",
         "xfa/fgas/crt:unittests",
+        "xfa/fgas/font:unittests",
         "xfa/fgas/layout:unittests",
         "xfa/fxfa:unittests",
         "xfa/fxfa/fm2js:unittests",