Netbeans code completion/fix can see some JDK classes but not others

### Apache NetBeans version

Apache NetBeans 23

### What happened

Project is ant/classpath-based (i.e. no modulepath), and this occurs on both Oracle jdk 21.0.5, and Amazon Corretto 21.0.1. M1 based mac on sequoia. I have wiped out my netbeans cache directory and my netbeans config directory (~/Library/Application Support/Netbeans/23) with no effect. I also made sure to tell the mac not to steal the ctrl+space key combo.

As an example, code completion works fine for ArrayList and HashSet, but it can not, under any circumstances find anything in the java.sql package. e.g. type `PreparedS` and then it `ctrl-space` and it just says "No suggestions" or type `PreparedStatement p = null;` and hit `option-enter` or `ctrl-enter` and I get suggestions to create a class called PreparedSatement, but nothing offering to import it. If I go to manually type in `import java.sql.PrepredStatement` it starts giving me suggestions for package and eventually class names. And once the import is in the file, Netbeans will suggest it in subsequent editing.

However, if I start to type in `ArrayList`I sometimes get code completion suggestions, and code fix seems to figure it out.

While this is going on, I see things like this in the log. Although their appearance in the log does not correspond exactly to my attempts to use this feature.

```
INFO [org.netbeans.api.java.source.ElementHandle]: Cannot resolve: ElementHandle[kind=CLASS; sigs=com.sun.tools.javac.code.Types$HashCodeVisitor ]
INFO [org.netbeans.api.java.source.ElementHandle]: Resolved type is null for kind = INTERFACE
INFO [org.netbeans.api.java.source.ElementHandle]: Cannot resolve: ElementHandle[kind=INTERFACE; sigs=jdk.internal.module.ModuleHashes$HashSupplier ]
INFO [org.netbeans.api.java.source.ElementHandle]: Resolved type is null for kind = CLASS
INFO [org.netbeans.api.java.source.ElementHandle]: Cannot resolve: ElementHandle[kind=CLASS; sigs=com.sun.jmx.remote.security.HashedPasswordManager ]
INFO [org.netbeans.api.java.source.ElementHandle]: Resolved type is null for kind = CLASS
INFO [org.netbeans.api.java.source.ElementHandle]: Cannot resolve: ElementHandle[kind=CLASS; sigs=jdk.internal.classfile.impl.AbstractPoolEntry ]
INFO [org.netbeans.api.java.source.ElementHandle]: Resolved type is null for kind = CLASS
INFO [org.netbeans.api.java.source.ElementHandle]: Cannot resolve: ElementHandle[kind=CLASS; sigs=jdk.internal.module.SystemModuleFinders ]
INFO [org.netbeans.api.java.source.ElementHandle]: Resolved type is null for kind = CLASS
INFO [org.netbeans.api.java.source.ElementHandle]: Cannot resolve: ElementHandle[kind=CLASS; sigs=com.sun.tools.javac.util.Names ]
INFO [org.netbeans.api.java.source.ElementHandle]: Resolved type is null for kind = CLASS
```

### Language / Project Type / NetBeans Component

Java Ant Project, classpath based

### How to reproduce

As an example, code completion works fine for ArrayList and HashSet, can not, under any circumstances find anything in the java.sql package. e.g. type `PreparedS` and then it `ctrl-space` and it just says "No suggestions" or type `PreparedStatement p = null;` and hit `option-enter` or `ctrl-enter` and I get suggestions to create a class called PreparedSatement, but nothing offering to import it. If I go to manually type in `import java.sql.PrepredStatement` it starts giving me suggestions for package and eventually class names. And once the import is in the file, Netbeans will suggest it in subsequent editing.

However, if I start to type in `ArrayList`I sometimes get code completion suggestions, and code fix seems to figure it out.

### Did this work correctly in an earlier version?

No / Don't know

### Operating System

macos 15.0.1 on an M1

### JDK

Oracle JDK 21.0.5, also Amazon Corretto 21.0.1

### Apache NetBeans packaging

Apache NetBeans provided installer

### Anything else

Occurs most, if not all, of the time.

### Are you willing to submit a pull request?

No

Start with the Java Ant classpath project and reproduce completion and code-fix behavior for java.sql.PreparedStatement versus ArrayList. Then trace the code-completion and ElementHandle paths associated with the reported log messages. Done means java.sql classes are suggested and offered for import consistently without the unresolved-element behavior.

Written by the indexing model from the issue text.