ci: speed up Windows phase

As Unix shell scripting comes at a hefty price on Windows, we have to
see where we can save some time to run the test suite.

Let's skip the chain linting and the bin-wrappers/ redirection on
Windows; this seems to shave of anywhere between 10-30% from the overall
runtime.

Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>

ci/lib.sh

@@ -127,6 +127,8 @@ then
 	export GIT_PROVE_OPTS="--timer --jobs 10 --state=failed,slow,save"
 	export GIT_TEST_OPTS="--verbose-log -x --write-junit-xml"
 	export MAKEFLAGS="--jobs=10"
+	test windows_nt != "$CI_OS_NAME" ||
+	GIT_TEST_OPTS="--no-chain-lint --no-bin-wrappers $GIT_TEST_OPTS"
 else
 	echo "Could not identify CI type" >&2
 	exit 1