merge(third_party/git): Merge squashed git subtree at v2.23.0

Merge commit '1b593e1ea4' as 'third_party/git'

third_party/git/t/t1003-read-tree-prefix.sh

@@ -0,0 +1,27 @@
+#!/bin/sh
+#
+# Copyright (c) 2006 Junio C Hamano
+#
+
+test_description='git read-tree --prefix test.
+'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+	echo hello >one &&
+	git update-index --add one &&
+	tree=$(git write-tree) &&
+	echo tree is $tree
+'
+
+echo 'one
+two/one' >expect
+
+test_expect_success 'read-tree --prefix' '
+	git read-tree --prefix=two/ $tree &&
+	git ls-files >actual &&
+	cmp expect actual
+'
+
+test_done