Change JDK distribution source (#41626)

We had been obtaining JDK distributions from download.java.net. This
site is now presenting a certificate that does not list
download.java.net as a SAN. Therefore with host verification, the build
can not use this site. This commit switches to using download.oracle.com
which appears to be an alternative name for the same CNAME
download.oracle.com.edgekey.net. This allows our builds to resume.

distribution/build.gradle

@@ -235,7 +235,7 @@ String jdkBuild = jdkVersionMatcher.group(3)
 
 repositories {
   ivy {
-    url "https://download.java.net"
+    url "https://download.oracle.com"
     patternLayout {
       artifact "java/GA/jdk${jdkMajor}/${jdkBuild}/GPL/openjdk-[revision]_[module]-x64_bin.[ext]"
     }