ptest: Optionally strip build host tool info from installed files

ptest: Optionally strip build host tool info from installed files

Several packages (eg. acl, attr, openssl) install Makefiles or other build host
configuration files for ptest so that they can run `make check`, for instance.
These build host files commonly include paths and versions of build host tools,
(eg. rpm or perl) whose presence and version depends on the build host distro.

Optionally strip lines from installed PTEST_BUILD_HOST_FILES using an
extended regex pattern defined in PTEST_BUILD_HOST_PATTERN. This has no
effect on the on-target ptest.

Signed-off-by: Douglas Royds <douglas.royds@taitradio.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>