Stream::makeFilter: Fix memory leak

fixes oss-fuzz/9614
5 jobs for basestreamstrem in 10 minutes and 28 seconds (queued for 5 seconds)
Status Job ID Name Coverage
  Build
passed #43167
build

00:07:12

passed #43168
build_clang_libcpp

00:07:04

passed #43171
build_clazy

00:04:03

passed #43169
build_gcc_49

00:10:27

passed #43170
build_mingw64_fedora

00:04:31