Implement search from expect element in KotlinReferenceSearcher

So mostly #KT-17512 Fixed

idea/testData/multiModuleFindUsages/findCommonClassFromActual/common/common.kt

@@ -0,0 +1,8 @@
+fun test() {
+    My("a").boo()
+    My("b").boo()
+}
+
+expect class My(val s: String) {
+    fun boo()
+}

idea/testData/multiModuleFindUsages/findCommonClassFromActual/jvm/jvm.kt

@@ -0,0 +1,6 @@
+// PSI_ELEMENT: org.jetbrains.kotlin.psi.KtClass
+// OPTIONS: usages, expected
+
+actual class <caret>My(val s: String) {
+    actual fun boo() {}
+}

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

@@ -0,0 +1,2 @@
+[common.kt] New instance creation 2 My("a").boo()
+[common.kt] New instance creation 3 My("b").boo()