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

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

third_party/git/t/chainlint/while-loop.test

@@ -0,0 +1,19 @@
+(
+# LINT: 'while, 'do', 'done' do not need "&&"
+	while true
+	do
+# LINT: missing "&&" on 'echo'
+		echo foo
+# LINT: last statement of while does not need "&&"
+		cat <<-\EOF
+		bar
+		EOF
+# LINT: missing "&&" on 'done'
+	done
+
+# LINT: 'do' on same line as 'while'
+	while true; do
+		echo foo &&
+		cat bar
+	done
+)