patch 9.0.1656: syntax test fails when detected shell type differs
Problem: Syntax test fails when detected shell type differs.
Solution: Avoid using "/bin/sh", it depends on the system. Add a check that
the shell type detection is correct.
diff --git a/runtime/syntax/testdir/input/sh_09.sh b/runtime/syntax/testdir/input/sh_09.sh
index 9888ade..e736e06 100644
--- a/runtime/syntax/testdir/input/sh_09.sh
+++ b/runtime/syntax/testdir/input/sh_09.sh
@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/dash
# Test file for vim the check () subshells
( cd ; $pwd ) | wc -c
( cd $1 ; $pwd ) | wc -c