ci: remove host parameter from LuaJIT testing

As a result of the commit 1eb0a696 ("ci:
change runner dispatch for LuaJIT testing") <inputs.host> parameter has
become obsolete. The testing workflow has been updated in scope of the
commit tarantool/luajit@fcaecf8fb42ff8a35582fbd8d034eb6f3b9b5b68 ("ci:
use strategy matrix for integration workflow"). Hence, the only changes
required to finish the transition from <inputs.host> to <inputs.arch> +
<inputs.os> are the following:
* Drop <inputs.host> parameter from the LuaJIT integration workflow
* Make both <inputs.arch> and <inputs.os> parameters obligatory

Besides, there is no need to obtain the kernel name and the machine
hardware name in scope of the separate workflow step, since all info
need to be passed to .test.mk is already passed via workflow inputs.
Anyway, .test.mk need to be adjusted to the values used for the new
workflow parameters.

NO_DOC=ci
NO_TEST=ci
NO_CHANGELOG=ci

Reviewed-by: Yaroslav Lobankov <y.lobankov@tarantool.org>
Signed-off-by: Igor Munkin <imun@tarantool.org>