Implement search from expect element in KotlinReferenceSearcher

So mostly #KT-17512 Fixed

idea/testData/multiModuleFindUsages/findCommonPropertyFromActual/common/common.kt

@@ -0,0 +1,8 @@
+fun test() {
+    use(boo)
+    use(boo)
+}
+
+fun use(arg: Int) {}
+
+expect val boo: Int

idea/testData/multiModuleFindUsages/findCommonPropertyFromActual/jvm/jvm.kt

@@ -0,0 +1,4 @@
+// PSI_ELEMENT: org.jetbrains.kotlin.psi.KtProperty
+// OPTIONS: usages, expected
+
+actual val <caret>boo: Int get() = 42

idea/testData/multiModuleFindUsages/findCommonPropertyFromActual/jvm/jvm.results.txt

@@ -0,0 +1,2 @@
+[common.kt] Value read 2 use(boo)
+[common.kt] Value read 3 use(boo)