JS backend: fix "is Boolean" check.

js/js.translator/testData/rtti/cases/isJsPrimitiveType.kt

@@ -0,0 +1,32 @@
+package foo
+
+enum class Type {
+    NUMBER
+    STRING
+    BOOLEAN
+    OBJECT
+}
+
+fun test(a: Any, actualType: Type) {
+    assertEquals(actualType == Type.NUMBER, a is Int, "$a is Int")
+    assertEquals(actualType == Type.NUMBER, a is Number, "$a is Number")
+    assertEquals(actualType == Type.NUMBER, a is Double, "$a is Double")
+    assertEquals(actualType == Type.BOOLEAN, a is Boolean, "$a is Boolean")
+    assertEquals(actualType == Type.STRING, a is String, "$a is String")
+}
+
+fun box(): String {
+    test(1, Type.NUMBER)
+
+    test(12.3, Type.NUMBER)
+    test(12.3f, Type.NUMBER)
+
+    test("text", Type.STRING)
+
+    test(true, Type.BOOLEAN)
+    test(false, Type.BOOLEAN)
+
+    test(object {}, Type.OBJECT)
+
+    return "OK"
+}