Revert "tests: add a file triggering a memory leak in dhcp_lease_parse_search_domains"

Revert "tests: add a file triggering a memory leak in dhcp_lease_parse_search_domains"

The test fails on this branch:

 948/1228 fuzz-dhcp-client_minimized-from-555a2b073b8d208655b68c294f8dfd592a11e50a_address,undefined                                      FAIL           0.00s (exit status 127)12:43
--- command ---12:43
01:47:36 UBSAN_OPTIONS='print_stacktrace=1:print_summary=1:halt_on_error=1' /usr/bin/env /tmp/autopkgtest-lxc.cl7c6fs0/downtmp/build.X6Z/src/build-deb/fuzz-dhcp-client:address,undefined /tmp/autopkgtest-lxc.cl7c6fs0/downtmp/build.X6Z/src/test/fuzz/fuzz-dhcp-client/minimized-from-555a2b073b8d208655b68c294f8dfd592a11e50a12:43
--- stderr ---12:43
/usr/bin/env: ‘/tmp/autopkgtest-lxc.cl7c6fs0/downtmp/build.X6Z/src/build-deb/fuzz-dhcp-client:address,undefined’: No such file or directory

This reverts commit 87728a590ad82391e76a275024c9039625ff2b67.