Referencing arbitrary `Builder` class inside Thread::run() causes compilation to fail with `java.lang.Thread.Builder is a preview API and is disabled by default` error.

OpenJDK version:

```
openjdk version "19-ea" 2022-09-20
OpenJDK Runtime Environment (build 19-ea+25-1892)
OpenJDK 64-Bit Server VM (build 19-ea+25-1892, mixed mode, sharing)
```

Reproducer sample class:
```
package com.example;

public class Builder {
    public static void main(String[] args) {
        new Thread() {
            public void run() {
                final Builder builder = new com.example.Builder();
                builder.buildNow();
            }
        }.start();
    }
    
    public void buildNow() {
    }
}
```


Compiler error (using "$JAVA_HOME/bin/javac" com/example/Builder.java):
```
src\main\java\com\example\Builder.java:7: error: Builder is a preview API and is disabled by default.
                final Builder builder = new com.example.Builder();
                      ^
  (use --enable-preview to enable preview APIs)
src\main\java\com\example\Builder.java:7: error: incompatible types: com.example.Builder cannot be converted to java.lang.Thread.Builder
                final Builder builder = new com.example.Builder();
                                        ^
src\main\java\com\example\Builder.java:8: error: cannot find symbol
                builder.buildNow();
                       ^
  symbol: method buildNow()
  location: variable builder of type Builder
3 errors
```

The issue has been manifested in Apache CXF builds which we run regularly for every JDK early releases, it is a bit difficult to precisely pinpoint the build but it has been noticed first time in the OpenJDK 19-ea+22 and confirmed in 19-ea+25.

[1] https://ci-builds.apache.org/job/CXF/job/CXF-JDK19/189/console