Propagate Rewind() errors in ScanlineDecoder::SkipToScanline()

JpegDecoder::Rewind() can fail and destroy the jpeg context in the
process.

Rewind() failures should be propagated upstream, similar to
ScanlineDecoder::GetScanline(), to avoid attempting to continue with
an invalid context.

Bug: 401846968
Change-Id: I73e1d9ddc51745be0706fe74d93558f5683fbfa8
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/129450
Reviewed-by: Thomas Sepez <tsepez@google.com>
Commit-Queue: Thomas Sepez <tsepez@google.com>
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Florin Malita <fmalita@chromium.org>

core/fxcodec/scanlinedecoder.cpp

diff --git a/core/fxcodec/scanlinedecoder.cpp b/core/fxcodec/scanlinedecoder.cpp
index bce71b9..3bb766e 100644
--- a/core/fxcodec/scanlinedecoder.cpp
+++ b/core/fxcodec/scanlinedecoder.cpp
@@ -52,7 +52,9 @@
     return false;
 
   if (m_NextLine < 0 || m_NextLine > line) {
-    Rewind();
+    if (!Rewind()) {
+      return false;
+    }
     m_NextLine = 0;
   }
   m_pLastScanline = pdfium::span<uint8_t>();