Upgrade the bundled JDK to JDK 15 (#62580)

This commit upgrades the bundled JDK to JDK 15.

Author: rjernst

distribution/docker/build.gradle

@@ -23,8 +23,8 @@ ext.expansions = { oss, local ->
     'build_date'          : project.buildDate,
     'elasticsearch'       : elasticsearch,
     'git_revision'        : project.gitRevision,
-    'jdkUrl'              : 'https://github.com/AdoptOpenJDK/openjdk14-binaries/releases/download/jdk-14.0.1%2B7/OpenJDK14U-jdk_x64_linux_hotspot_14.0.1_7.tar.gz',
-    'jdkVersion'          : '14.0.1+7',
+    'jdkUrl'              : 'https://github.com/AdoptOpenJDK/openjdk15-binaries/releases/download/jdk-15%2B36/OpenJDK15U-jdk_x64_linux_hotspot_15_36.tar.gz',
+    'jdkVersion'          : '15+36',
     'license'             : oss ? 'Apache-2.0' : 'Elastic-License',
     'source_elasticsearch': local ? "COPY $elasticsearch /opt/" : "RUN cd /opt && curl --retry 8 -s -L -O https://artifacts.elastic.co/downloads/elasticsearch/${elasticsearch} && cd -",
     'version'             : VersionProperties.elasticsearch