Fix develop CI: GCC 4.8, Clang 3.4 and clang-tidy errors

- unit-json_patch.cpp: move multi-line raw strings out of CHECK(), which
  GCC 4.8 cannot parse inside a macro argument
- unit-recursion_depth_limit.cpp: value-initialize the const std::hash
  (Clang 3.4 rejects default initialization of a const object)
- json_view: silence modernize-use-transparent-functors (std::less<> is
  C++14), bugprone-suspicious-stringview-data-usage (the length comes from
  the node) and the deliberate use-after-clear() / owning-memory hits in
  unit-json_view_builder.cpp; use a raw string literal there

Signed-off-by: Niels Lohmann <mail@nlohmann.me>

include/nlohmann/detail/view/document_data.hpp

@@ -158,7 +158,8 @@ struct document_data
     {
         const auto overlaps = [p, n](const char* b, std::size_t m) noexcept
         {
-            // (std::less: a total order also for pointers into different objects)
+            // (std::less: a total order also for pointers into different objects; std::less<> needs C++14)
+            // NOLINTNEXTLINE(modernize-use-transparent-functors)
             return n != 0 && m != 0 && std::less<const char*>()(p, b + m) && std::less<const char*>()(b, p + n);
         };
         return overlaps(owned.data(), owned.capacity())