Fix compile error in builder test harness under javac

[datho7561]

When compiling the builder tests with javac, a "failed to infer type parameters" compiler error is generated.

The following minimal example also produces the compiler error under javac (but not ECJ):

import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;

public class HelloWorld {
	public static void main(String... args) {
		Class[] classes = new Class[] { String.class, List.class };
		List<Class<?>> asdf = new ArrayList<>(Arrays.asList(classes));
	}
}

It's unclear to me which compiler is doing the wrong thing. The code change I made seems to compile under both compilers.

What it does

Fix a compile error in the builder test harness when compiling under javac.

How to test

To reproduce the compiler error (before this change), add the following to the ./org.eclipse.jdt.core.tests.builder/pom.xml "<plugins>" section to configure Tycho to run with javac:

<plugin>
  <groupId>org.eclipse.tycho</groupId>
  <artifactId>tycho-compiler-plugin</artifactId>
  <configuration>
    <compilerArgs>
      <args></args>
    </compilerArgs>
    <deriveReleaseCompilerArgumentFromTargetLevel>false</deriveReleaseCompilerArgumentFromTargetLevel>
    <compilerId>javac</compilerId>
</plugin>

Then, clean and compile the test bundle (mvn clean compile).

Author checklist

• I have thoroughly tested my changes
• The change is following the coding conventions
• I have signed the Eclipse Contributor Agreement (ECA)

[jukzi]

Please create and link an issue that there is a javac incompatibility quoting the reproducer, as this PR would be closed but the incompatibility remains.

[datho7561]

see #3588