Fix printing of stats when aborted. (#6362)

This PR improves/fixes printing of statistics when the solver has been aborted, i.e. when we use printSafe(), and a few other minor issues with the new statistics setup.

add toString() methods for TypeConstant, api::Kind to allow for automatic printing by print_safe<>()
improve kindToString() to avoid std::stringstream
fix newlines between statistics in printSafe()
make printing of histograms consistent
make --stats-all, --stats-expert and --stats-every-check automatically enable --stats (and vice versa)

2 files changed, 1 insertions, 3 deletions

diff --git a/src/util/statistics_registry.cpp b/src/util/statistics_registry.cpp
index ebd16ebc0..51da36aba 100644
--- a/src/util/statistics_registry.cpp
+++ b/src/util/statistics_registry.cpp
@@ -97,7 +97,7 @@ void StatisticsRegistry::printSafe(int fd) const
       safe_print(fd, s.first);
       safe_print(fd, " = ");
       s.second->printSafe(fd);
-      safe_print(fd, '\n');
+      safe_print(fd, "\n");
     }
   }
 }
diff --git a/src/util/statistics_value.h b/src/util/statistics_value.h
index 09f429187..950bdd4ab 100644
--- a/src/util/statistics_value.h
+++ b/src/util/statistics_value.h
@@ -154,11 +154,9 @@ struct StatisticHistogramValue : StatisticBaseValue
         {
           safe_print(fd, ", ");
         }
-        safe_print(fd, "(");
         safe_print<Integral>(fd, static_cast<Integral>(i + d_offset));
         safe_print(fd, ": ");
         safe_print<uint64_t>(fd, d_hist[i]);
-        safe_print(fd, ")");
       }
     }
     safe_print(fd, " }");