Introduce intention 'expr.unsafeCast<Type>()' <- -> 'expr as Type'

So #KT-16382 Fixed

idea/testData/intentions/convertUnsafeCastCallToUnsafeCast/.intention

@@ -0,0 +1 @@
+org.jetbrains.kotlin.idea.intentions.ConvertUnsafeCastCallToUnsafeCastIntention

idea/testData/intentions/convertUnsafeCastCallToUnsafeCast/call.kt

@@ -0,0 +1,4 @@
+// JS
+fun test(foo: dynamic) {
+    val s = <caret>foo.unsafeCast<String>()
+}

idea/testData/intentions/convertUnsafeCastCallToUnsafeCast/call.kt.after

@@ -0,0 +1,4 @@
+// JS
+fun test(foo: dynamic) {
+    val s = <caret>foo as String
+}

idea/testData/intentions/convertUnsafeCastCallToUnsafeCast/safeCall.kt

@@ -0,0 +1,5 @@
+// JS
+// IS_APPLICABLE: false
+fun test(foo: Any?) {
+    val s = <caret>foo?.unsafeCast<String>()
+}