test972: verify the output without using external tool

It seems too restrictive to assume and use an external tool to verify
the JSON. This now verifies the outut byte per byte. We could consider
building a local "JSON verifyer" in a future.

Remove 'jsonlint' from the CI job.

Reported-by: Marcel Raad
Fixes #9563
Closes #9564

.azure-pipelines.yml

@@ -59,7 +59,7 @@ stages:
       matrix:
         default:
           name: default
-          install: jsonlint
+          install:
           configure: --enable-debug --with-openssl
         disable_ipv6:
           name: w/o IPv6

tests/data/test972

@@ -28,9 +28,7 @@ Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor i
 #
 # Client-side
 <client>
-<precheck>
-/usr/bin/which jsonlint-php >log/%TESTNUMBER-check
-</precheck>
+
 <server>
 http
 </server>
@@ -47,7 +45,7 @@ CURL_VERSION=curl-unit-test-fake-version
 Verify JSON output
 </name>
 <command option="no-include">
-http://%HOSTIP:%HTTPPORT/%TESTNUMBER -s --write-out '%{json}' -o log/out972 | jsonlint-php -q
+http://%HOSTIP:%HTTPPORT/%TESTNUMBER -s --write-out '%{json}\n' -o log/out972
 </command>
 </client>
 
@@ -61,5 +59,8 @@ User-Agent: curl/%VERSION
 Accept: */*
 
 </protocol>
+<stdout mode="text">
+{"content_type":"text/html","errormsg":null,"exitcode":0,"filename_effective":"log/out972","ftp_entry_path":null,"http_code":200,"http_connect":0,"http_version":"1.1","local_ip":"%HOSTIP","local_port":13,"method":"GET","num_connects":1,"num_headers":9,"num_redirects":0,"proxy_ssl_verify_result":0,"redirect_url":null,"referer":null,"remote_ip":"%HOSTIP","remote_port":%HTTPPORT,"response_code":200,"scheme":"HTTP","size_download":445,"size_header":4019,"size_request":4019,"size_upload":0,"speed_download":13,"speed_upload":13,"ssl_verify_result":0,"time_appconnect":0.000013,"time_connect":0.000013,"time_namelookup":0.000013,"time_pretransfer":0.000013,"time_redirect":0.000013,"time_starttransfer":0.000013,"time_total":0.000013,"url":"http://%HOSTIP:%HTTPPORT/%TESTNUMBER","url_effective":"http://%HOSTIP:%HTTPPORT/%TESTNUMBER","urlnum":0,"curl_version":"curl-unit-test-fake-version"}
+</stdout>
 </verify>
 </testcase>