Evaluate expression: add ability to evaluate expression suspending on class header

idea/testData/debugger/tinyApp/src/evaluate/singleBreakpoint/onClassHeader.kt

@@ -0,0 +1,31 @@
+package onClassHeader
+
+fun main(args: Array<String>) {
+    val d: Base<String> = Derived()
+    //Breakpoint!
+    d.foo("")
+    val a = 1
+}
+
+open class Base<T> {
+    open fun foo(t: T): Int {
+        return 1
+    }
+}
+
+class Derived: Base<String>() {
+    override fun foo(t: String): Int {
+        return 2
+    }
+}
+
+// STEP_INTO: 2
+
+// EXPRESSION: 1 + 1
+// RESULT: 2: I
+
+// EXPRESSION: this
+// RESULT: instance of onClassHeader.Derived(id=ID): LonClassHeader/Derived;
+
+// EXPRESSION: this.foo("a")
+// RESULT: 2: I