test787: fix possible typo `&` -> `%` in curl option
They are close on the keyboard and don't affect test results.
To make this test XML-compliant.
Ref: #14479
Follow-up to 40c264db617d025ca5053bc0964a185d11101301 #15739
Closes #19826
diff --git a/tests/data/test787 b/tests/data/test787
index e95a18d..47b2eff 100644
--- a/tests/data/test787
+++ b/tests/data/test787
@@ -3,7 +3,6 @@
<keywords>
HTTP
--variable
-notxml
</keywords>
</info>
@@ -22,7 +21,7 @@
--variable with a file byte range, bad range
</name>
<command>
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[15-14]@&LOGDIR/fooo" --expand-data '{{name}}'
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER --variable "name[15-14]@%LOGDIR/fooo" --expand-data '{{name}}'
</command>
</client>