Inline val: more correct and simple detection of write usages

#KT-17489 Fixed

idea/testData/refactoring/inline/inlineVariableOrProperty/AppendToCollection.kt

@@ -0,0 +1,4 @@
+fun foo(list: MutableList<Int>) {
+    val <caret>list1 = list
+    list1 += 10
+}

idea/testData/refactoring/inline/inlineVariableOrProperty/AppendToCollection.kt.after

@@ -0,0 +1,3 @@
+fun foo(list: MutableList<Int>) {
+    list += 10
+}

idea/testData/refactoring/inline/inlineVariableOrProperty/property/KT17489.kt

@@ -0,0 +1,10 @@
+class Predicate(val x: Int) {
+    operator fun plusAssign(y: Int) {}
+
+    operator fun unaryMinus() = Predicate(-x)
+}
+
+fun test(p: Predicate) {
+    val <caret>x = -p
+    x += 42
+}

idea/testData/refactoring/inline/inlineVariableOrProperty/property/KT17489.kt.after

@@ -0,0 +1,9 @@
+class Predicate(val x: Int) {
+    operator fun plusAssign(y: Int) {}
+
+    operator fun unaryMinus() = Predicate(-x)
+}
+
+fun test(p: Predicate) {
+    -p += 42
+}