Remove failing DCHECK() in PDFiumPage::GetTextRunInfo()

This DCHECK() makes an assumption about PDFium behavior that is not 100%
correct, so it occasionally fails. Just remove it as failing the
DCHECK() does not affect the rest of the method.

Bug: 1277301
Change-Id: Ic318af014112fde60166c63dd0708ebbe84f72f4
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4549669
Reviewed-by: K. Moon <kmoon@chromium.org>
Commit-Queue: Lei Zhang <thestig@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1146755}

pdf/pdfium/pdfium_page.cc

@@ -487,9 +487,6 @@ absl::optional<AccessibilityTextRunInfo> PDFiumPage::GetTextRunInfo(
           ? GetFloatCharRectInPixels(page, text_page, start_char_index)
           : gfx::RectF();
 
-  // Pdfium trims more than 1 consecutive spaces to 1 space.
-  DCHECK_LE(actual_start_char_index - start_char_index, 1);
-
   int char_index = actual_start_char_index;
 
   // Set text run's style info from the first character of the text run.