Revert "[libc] Add LIBC_FULL_BUILD guard to stdint_proxy.h (#191234)" (#191273)

This reverts commit 63c64fa6cd.

libc/hdr/stdint_proxy.h

@@ -13,10 +13,6 @@
 // that is `libc.include.stdint` is added to the dependency of all targets
 // that use <stdint.h> header.
 
-#ifdef LIBC_FULL_BUILD
-#include "include/llvm-libc-macros/stdint-macros.h"
-#else
 #include <stdint.h>
-#endif
 
 #endif // LLVM_LIBC_HDR_STDINT_PROXY_H