Add Safe Delete tests for extension functions and properties

idea/testData/safeDelete/deleteProperty/kotlinPropertyWithJava/propertyExt.java

@@ -0,0 +1,7 @@
+package test;
+
+class A {
+    void bar() {
+        TestPackage.getFoo("");
+    }
+}

idea/testData/safeDelete/deleteProperty/kotlinPropertyWithJava/propertyExt.kt

@@ -0,0 +1,5 @@
+package test
+
+import test.foo
+
+val String.<caret>foo = "foo"

idea/testData/safeDelete/deleteProperty/kotlinPropertyWithJava/propertyExt.kt.messages

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