Generate proper initialization for possibly nullable SAM wrapper

#KT-18916 Fixed Target versions 1.1.5

compiler/testData/codegen/bytecodeText/sam/samWrapperForNullInitialization.kt

@@ -0,0 +1,26 @@
+// WITH_RUNTIME
+// FILE: JFoo.java
+
+import org.jetbrains.annotations.Nullable;
+
+public class JFoo {
+    public static void foo2(@Nullable Runnable h1, @Nullable Runnable h2) {
+        if (h2 != null) throw new AssertionError();
+        h1.run();
+    }
+}
+
+// FILE: Test.kt
+fun test() {
+    var i = 0
+    JFoo.foo2({ i++ }, null)
+}
+
+// @TestKt.class:
+// 1 NEW TestKt\$test\$1
+// 1 NEW kotlin/jvm/internal/Ref\$IntRef
+// 2 NEW
+// 1 INVOKESPECIAL TestKt\$test\$1.<init>
+// 0 IFNONNULL
+// 0 IFNULL
+// 1 ACONST_NULL

compiler/testData/codegen/bytecodeText/sam/samWrapperForNullableInitialization.kt

@@ -0,0 +1,24 @@
+// WITH_RUNTIME
+// FILE: JFoo.java
+
+import org.jetbrains.annotations.Nullable;
+
+public class JFoo {
+    public static void foo2(@Nullable Runnable h1, @Nullable Runnable h2) {
+        if (h2 != null) throw new AssertionError();
+        h1.run();
+    }
+}
+
+// FILE: Test.kt
+fun runnable(): (() -> Unit)? = null
+
+fun test() {
+    JFoo.foo2({}, runnable())
+}
+
+// @TestKt.class:
+// 2 NEW
+// 0 IFNONNULL
+// 1 IFNULL
+// 1 ACONST_NULL