[libc++] Header inclusion tests.

As mandated by the Standard's various synopses, e.g. [iterator.synopsis].
Searching the TeX source for '#include' is a good way to find all of these
mandates.

The new tests are all autogenerated by utils/generate_header_inclusion_tests.py.
I was SHOCKED by how many mandates there are, and how many of them
libc++ wasn't conforming with.

Differential Revision: https://reviews.llvm.org/D99309

GitOrigin-RevId: 2d0f1fa472a99dbb46735623363fe918feeda795
diff --git a/include/map b/include/map
index 9c3e5e6..ddb596f 100644
--- a/include/map
+++ b/include/map
@@ -480,6 +480,8 @@
 #include <__config>
 #include <__tree>
 #include <__node_handle>
+#include <compare>
+#include <initializer_list>
 #include <iterator> // __libcpp_erase_if_container
 #include <memory>
 #include <utility>