tool_getparam: make --url support a file with URLs

It implies -O used for each URL.

Mention in the --url documentation.

Test 488 and 489 verify.

Closes #16099

tests/data/test488

@@ -0,0 +1,63 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+--url
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data crlf="yes" nocheck="yes">
+HTTP/1.1 200 OK
+Date: Tue, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT
+ETag: "21025-dc7-39462498"
+Accept-Ranges: bytes
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+Funny-head: yesyes
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+<name>
+Download two URLs provided on stdin
+</name>
+<command>
+--url @-
+</command>
+<stdin>
+http://%HOSTIP:%HTTPPORT/a
+http://%HOSTIP:%HTTPPORT/b
+</stdin>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol crlf="yes">
+GET /a HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+
+GET /b HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+
+</protocol>
+</verify>
+</testcase>