runtime(sh): Do not look up a "sh" utility in $PATH for "sh_13.sh"

Dash may not be installed on a BSD CI runner, list it in the
shebang line.

See #17084
closes: #17094

Signed-off-by: Aliaksei Budavei <0x000c70@gmail.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>
diff --git a/runtime/syntax/testdir/dumps/sh_13_00.dump b/runtime/syntax/testdir/dumps/sh_13_00.dump
index 7fe0991..b65d187 100644
--- a/runtime/syntax/testdir/dumps/sh_13_00.dump
+++ b/runtime/syntax/testdir/dumps/sh_13_00.dump
@@ -1,4 +1,5 @@
->#+0#0000e05#ffffff0| |I|s@1|u|e| |#|1|7|0|2|6| |(|b|a|s|h| |h|i|g|h|l|i|g|h|t|i|n|g| |r|e|q|u|i|r|e|s| |s|p|a|c|e| |a|f|t|e|r| |$|(|)@1| +0#0000000&@15
+>#+0#0000e05#ffffff0|!|/|b|i|n|/|d|a|s|h| +0#0000000&@63
+|#+0#0000e05&| |I|s@1|u|e| |#|1|7|0|2|6| |(|b|a|s|h| |h|i|g|h|l|i|g|h|t|i|n|g| |r|e|q|u|i|r|e|s| |s|p|a|c|e| |a|f|t|e|r| |$|(|)@1| +0#0000000&@15
 |#+0#0000e05&| |h|t@1|p|s|:|/@1|g|i|t|h|u|b|.|c|o|m|/|v|i|m|/|v|i|m|/|i|s@1|u|e|s|/|1|7|0|2|6|#|i|s@1|u|e|c|o|m@1|e|n|t|-|2|7@1|4|1@1|2@1|8|4| +0#0000000&@9
 @75
 |_|c|o|m|p|_|c|o|m|p|g|e|n|_|s|p|l|i|t| |-+0#e000e06&|l| +0#0000000&|-+0#e000e06&@1| +0#0000000&|"+0#af5f00255&|$+0#e000e06&|(| +0#0000000&@45
@@ -16,5 +17,4 @@
 |~| @73
 |~| @73
 |~| @73
-|~| @73
-|i+0#0000000&|s|_|b|a|s|h|:| |1|,| @45|1|,|1| @10|A|l@1| 
+|i+0#0000000&|s|_|d|a|s|h|:| |1|,| |i|s|_|p|o|s|i|x|:| |1|,| |i|s|_|s|h|:| |1|,| @22|1|,|1| @10|A|l@1| 
diff --git a/runtime/syntax/testdir/input/sh_13.sh b/runtime/syntax/testdir/input/sh_13.sh
index a81c0a4..18fd0d1 100644
--- a/runtime/syntax/testdir/input/sh_13.sh
+++ b/runtime/syntax/testdir/input/sh_13.sh
@@ -1,3 +1,4 @@
+#!/bin/dash
 # Issue #17026 (bash highlighting requires space after $())
 # https://github.com/vim/vim/issues/17026#issuecomment-2774112284