Debugger: Do not use expression code fragments for evaluator (KT-32736, KT-32741)

It seems like it doesn't make much sense to create expression code fragments.
People type statements or several expressions separated with a semicolon to a single-line expression line.
That is exactly what block code fragment was designed for.

idea/jvm-debugger/jvm-debugger-test/testData/evaluation/singleBreakpoint/functionDeclaration.kt

@@ -0,0 +1,9 @@
+package functionDeclaration
+
+fun main() {
+    //Breakpoint!
+    val a = 5
+}
+
+// EXPRESSION: fun foo() {}
+// RESULT: VOID_VALUE