setting default proxy port from system property differs fromJDK standard

[kra3]

related to / can be clubbed with #1793

Describe the bug

As per JDK documentation of networking properties, if http.proxyPort is not set the default port (80 for http, 443 for https) will be taken.

However the AWS sdk implementation is setting the default to be zero 0.

PS: current implementation doesn't honor https variants (https.proxy*) also.

[debora-ito]

Acknowledged. Thank you for reaching out.