[libc][wctype] Move classification lookup tables to a cpp file (#174993)

#170525

Previously, lookup tables were defined in a header so that they can be
constexpr, but this lead to each translation unit having it's own copy,
bloating the library size. Looking at current usages of wctype
functions, they are always used at runtime, so there's no benefit of
having them constexpr, so I'm moving them to a cpp file, so that there's
only a single copy in the library.

Author: mleleszi

libc/src/__support/wctype/CMakeLists.txt

@@ -1,7 +1,9 @@
-add_header_library(
+add_object_library(
   wctype_classification_utils
   HDRS
     wctype_classification_utils.h
+  SRCS
+    wctype_classification_utils.cpp
   DEPENDS
     libc.hdr.types.wchar_t
     libc.hdr.stdint_proxy