testsuite: use binary output mode for custom curl test tools

Do not try to convert line-endings to CRLF on Windows by setting stdout
to binary mode, just like the curl tool does if --ascii is not specified.

This should prevent corrupted stdout line-ending output like CRCRLF.

In order to make the previously naive text-aware tests work with
binary mode on Windows, text-mode is disabled for them if it is not
actually part of the test case and line-endings are corrected.

tests/data/test543

@@ -28,7 +28,7 @@ curl_easy_escape
 # There's no MTDM in the protocol here since this code doesn't ask for the
 # time/date of the file
 <verify>
-<stdout mode="text">
+<stdout>
 %9C%26K%3DI%04%A1%01%E0%D8%7C%20%B7%EFS%29%FA%1DW%E1
 </stdout>
 </verify>