strings(1) is not conditional on WITH_/WITHOUT_TOOLCHAIN, as it is a small utility that is also useful outside of the toolchain context.

After switching to WITH_LLVM_BINUTILS by default (1cae7121c667), building world with default options and installing WITHOUT_TOOLCHAIN failed, because we would build LLVM's strings but attempt to install ELF Tool Chain's version. Address this by always including ELF Tool Chain strings in non-install make targets.

PR: 285556
Reported by: Michael Butler