labsjdk-ce-17 is back, use it by default as it more stable than 20-dev

Author: eregon

ci.jsonnet

@@ -229,7 +229,7 @@ local part_definitions = {
 
     v17: with_path {
       downloads+: {
-        JAVA_HOME: common.jdks["labsjdk-ee-17"],
+        JAVA_HOME: common.jdks["labsjdk-ce-17"],
       },
       environment+: {
         JT_JDK: "17",

tool/jt.rb

@@ -65,7 +65,7 @@
 ENV['GEM_HOME'] = File.expand_path(ENV['GEM_HOME']) if ENV['GEM_HOME']
 
 JDK_VERSIONS =  [17, 20]
-DEFAULT_JDK_VERSION = JDK_VERSIONS.last
+DEFAULT_JDK_VERSION = JDK_VERSIONS.first
 
 MRI_TEST_RELATIVE_PREFIX = 'test/mri/tests'
 MRI_TEST_PREFIX = "#{TRUFFLERUBY_DIR}/#{MRI_TEST_RELATIVE_PREFIX}"
@@ -175,12 +175,7 @@ def ee?
   end
 
   def ee_jdk?
-    if @jdk_version == 17
-      # No labsjdk-ce-17 in common.json
-      true
-    else
-      ee?
-    end
+    ee?
   end
 
   def jvmci_version