Enable clang-tidy bugprone-assert-side-effect

Official docs:

  Finds assert() with side effect. The condition of assert() is
  evaluated only in debug builds so a condition with side effect can
  cause different behavior in debug / release builds.

.clang-tidy

@@ -5,7 +5,6 @@ Checks: '*,
 
     -android-*,
 
-    -bugprone-assert-side-effect,
     -bugprone-branch-clone,
     -bugprone-dynamic-static-initializers,
     -bugprone-easily-swappable-parameters,

src/Processors/Formats/Impl/ParallelFormattingOutputFormat.cpp

@@ -161,7 +161,7 @@ namespace DB
         try
         {
             auto & unit = processing_units[current_unit_number];
-            assert(unit.status = READY_TO_FORMAT);
+            assert(unit.status == READY_TO_FORMAT);
 
             /// We want to preallocate memory buffer (increase capacity)
             /// and put the pointer at the beginning of the buffer