Extract some codegen tests to black box testData

compiler/testData/codegen/box/casts/as.kt

@@ -0,0 +1,8 @@
+fun foo(x: Any) = x as Runnable
+
+fun box(): String {
+	val r = object : Runnable {
+		override fun run() {}
+	}
+	return if (foo(r) identityEquals r) "OK" else "Fail"
+}

compiler/testData/codegen/box/casts/asSafe.kt

@@ -0,0 +1,8 @@
+fun foo(x: Any) = x as? Runnable
+
+fun box(): String {
+	val r = object : Runnable {
+		override fun run() {}
+	}
+	return if (foo(r) identityEquals r) "OK" else "Fail"
+}

compiler/testData/codegen/box/casts/is.kt

@@ -0,0 +1,8 @@
+fun foo(x: Any) = x is Runnable
+
+fun box(): String {
+	val r = object : Runnable {
+		override fun run() {}
+	}
+	return if (foo(r) && !foo(42)) "OK" else "Fail"
+}

compiler/testData/codegen/box/casts/notIs.kt

@@ -0,0 +1,8 @@
+fun foo(x: Any) = x !is Runnable
+
+fun box(): String {
+	val r = object : Runnable {
+		override fun run() {}
+	}
+	return if (!foo(r) && foo(42)) "OK" else "Fail"
+}

compiler/testData/codegen/box/extensionFunctions/simple.kt

@@ -1,3 +1,5 @@
 fun StringBuilder.first() = this.charAt(0)
 
 fun foo() = StringBuilder("foo").first()
+
+fun box() = if (foo() == 'f') "OK" else "Fail ${foo()}"

compiler/testData/codegen/box/extensionFunctions/whenFail.kt

@@ -12,3 +12,13 @@ fun foo(expr: StringBuilder): Int {
     else -> throw Exception("nonzero" + c)
   }
 }
+
+fun box(): String {
+  try {
+    foo(StringBuilder())
+    return "Fail"
+  }
+  catch (e: Exception) {
+    return "OK"
+  }
+}