Optimization to reuse BindingContext in completion

idea/idea-completion/testData/incrementalResolve/prevStatementNotResolved.kt

@@ -0,0 +1,17 @@
+fun foo(p1: Any, p2: Any) {
+    if (p1 !is String) return
+    val v1 = "a"
+    val v2 = 123
+    println("a")
+    bar(x<before><change>)
+    if (p2 !is String) return
+}
+
+fun bar(s: String){}
+
+// BACKSPACES: 1
+// COMPLETION_TYPE: SMART
+// EXIST: v1
+// ABSENT: v2
+// EXIST: p1
+// ABSENT: p2