Add missing <cassert> includes

Until recently we were probably getting it from some transitive
include, but it broke. Because all files should include what
they use anyway, adding `#include <cassert>` to all files that
use `assert()` without including it is the best solution.

Fixes #1249

include/reporters/catch_reporter_console.hpp

@@ -13,6 +13,7 @@
 #include "../internal/catch_reporter_registrars.hpp"
 #include "../internal/catch_console_colour.hpp"
 
+#include <cassert>
 #include <cfloat>
 #include <cstdio>
 

include/reporters/catch_reporter_teamcity.hpp

@@ -14,6 +14,7 @@
 // file can be distributed as a single header that works with the main
 // Catch single header.
 
+#include <cassert>
 #include <cstring>
 
 #ifdef __clang__