Analyze Data Flow: Support properties with custom accessors

#KT-11994 In Progress

idea/testData/slicer/outflow/getterExpressionBody.kt

@@ -0,0 +1,8 @@
+// FLOW: OUT
+
+val foo: Int
+    get() = <caret>0
+
+fun test() {
+    val x = foo
+}

idea/testData/slicer/outflow/getterExpressionBody.results.txt

@@ -0,0 +1,3 @@
+4 get() = <bold>0</bold>
+4 	<bold>get() = 0</bold>
+7 		val <bold>x = foo</bold>

idea/testData/slicer/outflow/getterReturnExpression.kt

@@ -0,0 +1,10 @@
+// FLOW: OUT
+
+val foo: Int
+    get(): Int {
+        return <caret>0
+    }
+
+fun test() {
+    val x = foo
+}

idea/testData/slicer/outflow/getterReturnExpression.results.txt

@@ -0,0 +1,3 @@
+5 return <bold>0</bold>
+4 	<bold>get(): Int {</bold>
+9 		val <bold>x = foo</bold>