Launching JNLP takes 20+ mins when launched through AdaptOpenJDK_1.8.0.275 and IcedWebTea_1.8.4

## Summary
When Launching jnlp file using AdaptOpenJDK_1.8.0.275 through IcedWebTea(1.8.4) its taking 20+ mins to launch it fully. From the same client machine when I use OracleJRE_1.8u261 it launches the jnlp console in less than 1 min.

Note: There is a latency between my client machine and the Tomcat webserver hosting the jnlp file. If I launch the jnlp file from the local Tomcat webserver application then it launches quickly. So it has the issue only when there is a latency between client and webserver. But Oracle JRE launches it quickly even though the latency is there.

Its a high priority issue for us. Our end customer is escalating this issue and hence any quick solutions/suggestions would be highly appreciated.

## Steps to reproduce
1. Download the jnlp file from our Tomcat webserver application.
2. Launch the jnlp with IcedWebTea(1.8.4) running on AdaptOpenJDK(1.8.0.275)
3. It takes ~20mns to launch the client console.
4. From the same client machine launch the jnlp using OracleJRE_1.8.261, it launches in less than 1 min.

## Expected results
Jnlp client console should be launched without delay.

## Actual results
Jnlp client console is getting launched with lot of delay.

## Triaging info

Java version: AdaptOpenJDK_1.8.0.275
IcedTeaWeb : 1.8.4

C:\Users\mb632587>java -version
openjdk version "1.8.0_275"
OpenJDK Runtime Environment (AdoptOpenJDK)(build 1.8.0_275-b01)
OpenJDK 64-Bit Server VM (AdoptOpenJDK)(build 25.275-b01, mixed mode)

What is your operating system and platform?
"Windows 10 Pro"

How did you install Java?
OpenJDK8U-jre_x64_windows_hotspot_8u275b01.msi
icedtea-web-1.8.4.msi

Did it work before?
No

Did you test with other Java versions?
Yes, tested with OracleJRE_1.8.261 and it worked fine.