testsuite: analyzer: Fix fd-glibc-byte-stream-connection-server.c on Solaris [PR107750]

testsuite: analyzer: Fix fd-glibc-byte-stream-connection-server.c on Solaris [PR107750]

gcc.dg/analyzer/fd-glibc-byte-stream-connection-server.c currently FAILs
on Solaris:

FAIL: gcc.dg/analyzer/fd-glibc-byte-stream-connection-server.c (test for
excess errors)

Excess errors:
/vol/gcc/src/hg/master/local/gcc/testsuite/gcc.dg/analyzer/fd-glibc-byte-stream-connection-server.c:91:3:
error: implicit declaration of function 'memset'
[-Wimplicit-function-declaration]

Solaris <sys/select.h> has

but no declaration of memset.  While one can argue that this should be
fixed, it's easy enough to just include <string.h> instead, which is
what this patch does.

Tested on i386-pc-solaris2.11 and i686-pc-linux-gnu.

2024-05-14  Rainer Orth  <ro@CeBiTec.Uni-Bielefeld.DE>

	gcc/testsuite:
	PR analyzer/107750
	* gcc.dg/analyzer/fd-glibc-byte-stream-connection-server.c:
	Include <string.h>.