ART: Change dchecked_integral_cast logging

Add error message that prints the actual value.

Bug: 37287051
Test: m test-art-host
Change-Id: If6bfbe95d65edab0bcd96cf573d11516287ce318
diff --git a/runtime/base/casts.h b/runtime/base/casts.h
index 6b67864..c5b0af6 100644
--- a/runtime/base/casts.h
+++ b/runtime/base/casts.h
@@ -98,7 +98,9 @@
       // Check that the value is within the upper limit of Dest.
       (static_cast<uintmax_t>(std::numeric_limits<Dest>::max()) >=
           static_cast<uintmax_t>(std::numeric_limits<Source>::max()) ||
-          source <= static_cast<Source>(std::numeric_limits<Dest>::max())));
+          source <= static_cast<Source>(std::numeric_limits<Dest>::max())))
+      << "dchecked_integral_cast failed for " << source
+      << " (would be " << static_cast<Dest>(source) << ")";
 
   return static_cast<Dest>(source);
 }