remove no-arg constructor from ToolProvider

Summary

An explicit constructor in ToolProvider, deprecated for removal, replaced a default constructor. The time has come to "remove" the constructor by making it private and thus on longer part of the external API of the class.

Problem

A deprecated-for-removal constructor is not yet removed from the API.

Solution

Remove the no-arg constructor by making it private.

Specification

 --- old/src/java.compiler/share/classes/javax/tools/ToolProvider.java  2020-07-17 10:26:50.446004000 -0700
+++ new/src/java.compiler/share/classes/javax/tools/ToolProvider.java   2020-07-17 10:26:49.794004000 -0700
@@ -44,11 +44,7 @@
     private static final String systemJavaCompilerModule = "jdk.compiler";
     private static final String systemJavaCompilerName   = "com.sun.tools.javac.api.JavacTool";

-    /**
-     * Do not call.
-     */
-    @Deprecated(forRemoval=true, since="14")
-    public ToolProvider() {}
+    private ToolProvider() {}

     /**
      * Returns the Java programming language compiler provided