[skip ci] Sync HAVE_SIGSETJMP removal

This adds notice in the UPGRADING.INTERNALS file and removes redundant
undefinition from Windows config header.

Follow-up of GH-14942.

Author: petk

UPGRADING.INTERNALS

@@ -107,6 +107,7 @@ PHP 8.4 INTERNALS UPGRADE NOTES
    - Symbol DBA_CDB_MAKE removed in ext/dba.
    - Symbol HAVE_LIBM has been removed.
    - Symbol HAVE_INET_ATON has been removed.
+   - Symbol HAVE_SIGSETJMP has been removed.
    - The Zend/zend_istdiostream.h header has been removed.
 
  b. Unix build system changes

win32/build/config.w32.h.in

@@ -48,7 +48,6 @@
 
 #define HAVE_GETCWD 1
 #undef HAVE_SETITIMER
-#undef HAVE_SIGSETJMP
 #undef HAVE_IODBC
 #define HAVE_LIBDL 1
 #define HAVE_GETTIMEOFDAY 1