Additional IEEE754-related tests for subject variable in 'when'

compiler/testData/codegen/box/when/whenSubjectVariable/ieee754EqualityWithSmartCast.kt

@@ -2,6 +2,7 @@
 // IGNORE_BACKEND: JS
 
 val az: Any = -0.0
+val afz: Any = -0.0f
 
 fun box(): String {
     when (val y = az) {
@@ -10,5 +11,11 @@ fun box(): String {
         else -> throw AssertionError()
     }
 
+    when (val y = afz) {
+        !is Float -> throw AssertionError()
+        0.0 -> {}
+        else -> throw AssertionError()
+    }
+
     return "OK"
 }