Add support for stripped host installation

Add option --[no-]strip to strip host binaries from symbols. Symbols usually
don't make sense for end users but waste a lot of space. If --strip option
is specified than host applications will be installed using target
install-strip, instead of default install. GDB and CGEN are not affected
because they do not support this install target and I don't want to
workaround this by stripping them manually from the script. Stripping is
optional, by default toolchain is with debug symbols.
(cherry picked from commit 92dfc0dfa77ba61c2125ec3caa45948e6938642d)
Fix double usage of same variable name

Signed-off-by: Anton Kolesov <akolesov@synopsys.com>
(cherry picked from commit 70e9b9a8e5a45e00b20a6bab84dea77b025d6699)