Add "Length1" entry to test bug_1752.in.

Add "Length1" entry to test bug_1752.in since this entry is a required
field for TrueType font. By adding this entry, Acrobat reader will
render "ABCD" without scaling down the glyph widths, which will be the
same behavior as other PDF viewing tools'.

Bug: pdfium:1752
Change-Id: I98574b8486d024d21dab1cf7a06d1d14bee7bf67
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/91832
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Nigi <nigi@chromium.org>
diff --git a/testing/resources/pixel/bug_1752.in b/testing/resources/pixel/bug_1752.in
index f9a602e..0ba4a41 100644
--- a/testing/resources/pixel/bug_1752.in
+++ b/testing/resources/pixel/bug_1752.in
@@ -63,6 +63,7 @@
 {{object 7 0}} <<
   /Filter [/ASCIIHexDecode /FlateDecode]
   {{streamlen}}
+  /Length1 11200
 >>
 stream
 {{include ../bug_1752_truetype_font.fragment}}