Merge branch 'js/test-git-installed'

Update the "test installed Git" mode of our test suite to work better.

* js/test-git-installed:
  tests: explicitly use `git.exe` on Windows
  tests: do not require Git to be built when testing an installed Git
  t/lib-gettext: test installed git-sh-i18n if GIT_TEST_INSTALLED is set
  tests: respect GIT_TEST_INSTALLED when initializing repositories
  tests: fix GIT_TEST_INSTALLED's PATH to include t/helper/

t/test-lib-functions.sh

@@ -923,7 +923,8 @@ test_create_repo () {
 	mkdir -p "$repo"
 	(
 		cd "$repo" || error "Cannot setup test environment"
-		"$GIT_EXEC_PATH/git-init" "--template=$GIT_BUILD_DIR/templates/blt/" >&3 2>&4 ||
+		"${GIT_TEST_INSTALLED:-$GIT_EXEC_PATH}/git$X" init \
+			"--template=$GIT_BUILD_DIR/templates/blt/" >&3 2>&4 ||
 		error "cannot run git init -- have you built things yet?"
 		mv .git/hooks .git/hooks-disabled
 	) || exit