Revert "oeqa: Set LD_LIBRARY_PATH when executing native commands"

LD_LIBRARY_PATH leaks into host executables too, and breaks them
as they are not uninative-enabled. E.g. on ubuntu 18.04 trying
to run host bash with a sysroot that was built on Fedora 33:

akanavin@ubuntu1804-ty-3:/home/pokybuild/yocto-worker/oe-selftest-ubuntu/build/build-st-24341/tmp/work/x86_64-linux/gnupg-native/2.3.1-r0/recipe-sysroot-native$ LD_LIBRARY_PATH=./usr/lib /bin/bash
/bin/bash: ./usr/lib/libtinfo.so.5: no version information available (required by /bin/bash)
/bin/bash: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.33' not found (required by ./usr/lib/libtinfo.so.5)

This was seen e.g. here:
https://autobuilder.yoctoproject.org/typhoon/#/builders/87/builds/2090/steps/14/logs/stdio



Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 0e985048)
Signed-off-by: Steve Sakoman <steve@sakoman.com>