Convert bounds-check from DCHECK() to CHECK() in JBig2_ArithDecoder

Bounds-checking shouldn't be debug only.

-- Remove somewhat redundant DCHECK().

Change-Id: I00cc188dddd4e1e90df1c60914deed377d1ab2be
Reviewed-on: https://pdfium-review.googlesource.com/c/pdfium/+/109590
Reviewed-by: Lei Zhang <thestig@chromium.org>
Commit-Queue: Tom Sepez <tsepez@chromium.org>
diff --git a/core/fxcodec/jbig2/JBig2_ArithDecoder.cpp b/core/fxcodec/jbig2/JBig2_ArithDecoder.cpp
index 2555ee2..625ebf2 100644
--- a/core/fxcodec/jbig2/JBig2_ArithDecoder.cpp
+++ b/core/fxcodec/jbig2/JBig2_ArithDecoder.cpp
@@ -66,8 +66,7 @@
 CJBig2_ArithDecoder::~CJBig2_ArithDecoder() = default;
 
 int CJBig2_ArithDecoder::Decode(JBig2ArithCtx* pCX) {
-  DCHECK(pCX);
-  DCHECK_LT(pCX->I(), std::size(kQeTable));
+  CHECK_LT(pCX->I(), std::size(kQeTable));
 
   const JBig2ArithCtx::JBig2ArithQe& qe = kQeTable[pCX->I()];
   m_A -= qe.Qe;