imgdiag: Change CHECK_NE() to LOG(ERROR).

We've seen enough flakes, so reduce the spam while
we investigate.

Test: imgdiag_test
Bug: 123852774
Change-Id: Ia8017f93e23d73c8393588c529b1fa9f0a3f88db
diff --git a/imgdiag/imgdiag.cc b/imgdiag/imgdiag.cc
index 7166395..90563a1 100644
--- a/imgdiag/imgdiag.cc
+++ b/imgdiag/imgdiag.cc
@@ -1728,8 +1728,13 @@
     // page_frame_number_clean must come from the *same* process
     // but a *different* mmap than page_frame_number
     if (flags_dirty) {
-      CHECK_NE(page_frame_number, page_frame_number_clean)
-          << " count: " << *page_count << " flags: 0x" << std::hex << kpage_flags_entry;
+      // FIXME: This check sometimes fails and the reason is not understood. b/123852774
+      if (page_frame_number != page_frame_number_clean) {
+        LOG(ERROR) << "Check failed: page_frame_number != page_frame_number_clean "
+            << "(page_frame_number=" << page_frame_number
+            << ", page_frame_number_clean=" << page_frame_number_clean << ")"
+            << " count: " << *page_count << " flags: 0x" << std::hex << kpage_flags_entry;
+      }
     }
 
     return page_frame_number != page_frame_number_clean;