fixed bug: 'isStatement' for function body == 'hasBlockBody'

not vice versa

compiler/testData/diagnostics/tests/controlStructures/ForbidStatementAsDirectFunctionBody.kt

@@ -0,0 +1,11 @@
+
+fun foo1() = <!EXPRESSION_EXPECTED!>while (b()) {}<!>
+
+fun foo2() = <!EXPRESSION_EXPECTED!>for (<!UNUSED_PARAMETER!>i<!> in <!ITERATOR_MISSING!>10<!>) {}<!>
+
+fun foo3() = when (b()) {
+    true -> 1
+    else -> 0
+}
+
+fun b(): Boolean = true