Remove stale clang ranges guards in unit-iterators2.cpp

The "algorithms" and "views" sections were guarded by clang/libstdc++
checks written for a clang 15 (04/2022) bug. The first guard's
condition contradicts its own comment: it skips clang+libc++ and
keeps clang+libstdc++. Both sections already sit inside
`#if JSON_HAS_RANGES`, which macro_scope.hpp excludes for the
toolchains these guards targeted, so the inner guards never let the
sections run on the platforms they meant to protect and are
redundant on the rest. Verified locally with Apple clang 21/libc++
and clang 16.0.6/libstdc++ 12 (Docker): both pass all 1355
assertions with the guards removed.

Part of #5713

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

tests/src/unit-iterators2.cpp

@@ -893,8 +893,6 @@ TEST_CASE("iterators 2")
             CHECK(std::ranges::input_range<items_type>);
         }
 
-        // libstdc++ algorithms don't work with Clang 15 (04/2022)
-#if !DOCTEST_CLANG || (DOCTEST_CLANG && defined(__GLIBCXX__))
         SECTION("algorithms")
         {
             SECTION("copy")
@@ -929,11 +927,7 @@ TEST_CASE("iterators 2")
                 CHECK(*it == 2);
             }
         }
-#endif
 
-        // libstdc++ views don't work with Clang 15 (04/2022)
-        // libc++ hides limited ranges implementation behind guard macro
-#if !(DOCTEST_CLANG && (defined(__GLIBCXX__) || defined(_LIBCPP_HAS_NO_INCOMPLETE_RANGES)))
         SECTION("views")
         {
             SECTION("reverse")
@@ -966,7 +960,6 @@ TEST_CASE("iterators 2")
                 CHECK(j_transformed == j_expected);
             }
         }
-#endif
     }
 #endif
 }