Fix for KT-15868: NPE when comparing nullable doubles

#KT-15868 Fixed

compiler/testData/codegen/box/ieee754/nullableIntEquals.kt

@@ -0,0 +1,26 @@
+//NB: special ieee754 arithmetic logic is not applied to Int comparison
+fun myEquals(a: Int?, b: Int?) = a == b
+
+fun myEquals1(a: Int?, b: Int) = a == b
+
+fun myEquals2(a: Int, b: Int?) = a == b
+
+fun myEquals0(a: Int, b: Int) = a == b
+
+
+fun box(): String {
+    if (!myEquals(null, null)) return "fail 1"
+    if (myEquals(null, 0)) return "fail 2"
+    if (myEquals(0, null)) return "fail 3"
+    if (!myEquals(0, 0)) return "fail 4"
+
+    if (myEquals1(null, 0)) return "fail 5"
+    if (!myEquals1(0, 0)) return "fail 6"
+
+    if (myEquals2(0, null)) return "fail 7"
+    if (!myEquals2(0, 0)) return "fail 8"
+
+    if (!myEquals0(0, 0)) return "fail 9"
+
+    return "OK"
+}