Add Safe Delete tests for extension functions and properties

idea/testData/safeDelete/deleteFunction/kotlinFunction/funExt1.kt

@@ -0,0 +1,11 @@
+package test
+
+import test.foo
+
+class B {
+
+}
+
+fun B.<caret>foo() {
+
+}

idea/testData/safeDelete/deleteFunction/kotlinFunction/funExt1.kt.after

@@ -0,0 +1,5 @@
+package test
+
+class B {
+
+}

idea/testData/safeDelete/deleteFunction/kotlinFunction/funExt2.kt

@@ -0,0 +1,11 @@
+package test
+
+import test.foo
+
+class B {
+    val ref = ::foo
+}
+
+fun B.<caret>foo() {
+
+}

idea/testData/safeDelete/deleteFunction/kotlinFunction/funExt2.kt.messages

@@ -0,0 +1 @@
+function test.foo has 1 usage that is not safe to delete.

idea/testData/safeDelete/deleteFunction/kotlinFunction/localFunExt1.kt

@@ -0,0 +1,7 @@
+fun foo() {
+    fun String.<caret>bar() {
+
+    }
+
+    "".bar()
+}

idea/testData/safeDelete/deleteFunction/kotlinFunction/localFunExt1.kt.messages

@@ -0,0 +1 @@
+function foo.bar has 1 usage that is not safe to delete.

idea/testData/safeDelete/deleteFunction/kotlinFunction/localFunExt2.kt

@@ -0,0 +1,7 @@
+fun foo() {
+    fun String.<caret>bar() {
+
+    }
+
+    println()
+}

idea/testData/safeDelete/deleteFunction/kotlinFunction/localFunExt2.kt.after

@@ -0,0 +1,4 @@
+fun foo() {
+
+    println()
+}