Use of sparse_array.c only in the shared libssl

Conditioning it on $disabled{shared} isn't right, it will still end up
in the static variant of the library.  It's better to use SHARED_SOURCE
for these sorts of things.

Fixes #20238

Reviewed-by: Hugo Landau <hlandau@openssl.org>
Reviewed-by: Ben Kaduk <kaduk@mit.edu>
Reviewed-by: Paul Dale <pauli@openssl.org>
(Merged from #20240)

(cherry picked from commit cd870db)

crypto/build.info

@@ -101,9 +101,7 @@ $UTIL_COMMON=\
         context.c sparse_array.c asn1_dsa.c packet.c param_build.c \
         param_build_set.c der_writer.c threads_lib.c params_dup.c
 
-IF[{- !$disabled{shared} -}]
-  SOURCE[../libssl]=sparse_array.c
-ENDIF
+SHARED_SOURCE[../libssl]=sparse_array.c
 
 SOURCE[../libcrypto]=$UTIL_COMMON \
         mem.c mem_sec.c \