zulu: Fix passthru.tests

* Eliminate duplicate passthru definition by moving "tests.version"
* Only compare major version (because the ".0.0" can be truncated
* Special case major version 8 to "1.8" for the comparison

pkgs/development/compilers/zulu/common.nix

@@ -3,6 +3,7 @@
   stdenv,
   fetchurl,
   setJavaClassPath,
+  testers,
   enableJavaFX ? false,
   dists,
   # minimum dependencies
@@ -141,11 +142,6 @@ let
         fi
       '';
 
-  passthru.tests.version = testers.testVersion {
-    package = jdk;
-    command = "java -version";
-    version = ''openjdk version "${if lib.versions.major version == "23" then "23" else version}"'';
-  };
     preFixup =
       ''
         # Propagate the setJavaClassPath setup hook from the ${if isJdk8 then "JRE" else "JDK"} so that
@@ -188,6 +184,13 @@ let
       })
       // {
         home = jdk;
+        tests.version = testers.testVersion {
+          package = jdk;
+          command = "java -version";
+          version = ''openjdk version \""${
+            if lib.versions.major version == "8" then "1.8" else lib.versions.major version
+          }"'';
+        };
       }
       // lib.optionalAttrs stdenv.hostPlatform.isDarwin {
         bundle = "${jdk}/Library/Java/JavaVirtualMachines/zulu-${lib.versions.major version}.jdk";