Introduce experimental -Xuse-javac compilation mode

In this mode, javac AST and Symbol files are used during
Kotlin compilation instead of PSI / binary stuff.
Later, they are reused for Java file compilation.
javac in this mode is integrated into kotlinc.

build.xml

@@ -22,6 +22,9 @@
     <property name="javax.inject.jar" value="${basedir}/lib/javax.inject.jar"/>
     <property name="gradle.logging.level" value=""/>
 
+    <property environment="env"/>
+    <property name="tools.jar" value="${env.JDK_18}/lib/tools.jar"/>
+
     <property name="java.target" value="1.8"/>
     <property name="java.target.1.6" value="1.6"/>
 
@@ -56,6 +59,7 @@
         <file file="${bootstrap.script.runtime}"/>
         <fileset dir="${idea.sdk}" includes="core/*.jar"/>
         <pathelement location="${protobuf.jar}"/>
+        <pathelement location="${tools.jar}"/>
 
         <fileset dir="${basedir}/lib" includes="**/*.jar"/>
         <fileset dir="${dependencies}" includes="jansi.jar"/>
@@ -85,6 +89,7 @@
         <include name="compiler/ir/ir.psi2ir/src"/>
         <include name="compiler/ir/ir.tree/src"/>
         <include name="compiler/builtins-serializer/src"/>
+        <include name="compiler/javac-wrapper/src"/>
         <include name="compiler/cli/src"/>
         <include name="compiler/cli/cli-common/src"/>
         <include name="compiler/conditional-preprocessor/src/"/>
@@ -140,6 +145,7 @@
         <include name="plugin-api/**"/>
         <include name="annotation-collector/**"/>
         <include name="builtins-serializer/**"/>
+        <include name="javac-wrapper/**"/>
         <include name="js.ast/**"/>
         <include name="js.translator/**"/>
         <include name="js.frontend/**"/>
@@ -235,6 +241,7 @@
             <fileset dir="compiler/ir/ir.psi2ir/src"/>
             <fileset dir="compiler/ir/ir.tree/src"/>
             <fileset dir="compiler/builtins-serializer/src"/>
+            <fileset dir="compiler/javac-wrapper/src"/>
             <fileset dir="compiler/cli/src"/>
             <fileset dir="compiler/cli/cli-common/src"/>
             <fileset dir="compiler/conditional-preprocessor/src"/>