JS: fix behaviour of char-returning functions with multiple inheritance

See KT-19772

js/js.translator/testData/box/coercion/bridgeChar.kt

@@ -0,0 +1,41 @@
+// EXPECTED_REACHABLE_NODES: 1039
+open class A {
+    fun foo(): Char = 'X'
+}
+
+interface I {
+    fun foo(): Any
+}
+
+class B : A(), I
+
+fun typeOf(x: dynamic): String = js("typeof x")
+
+fun box(): String {
+    val b = B()
+    val i: I = B()
+    val a: A = B()
+
+    val r1 = typeOf(b.asDynamic().foo())
+    if (r1 != "object") return "fail1: $r1"
+
+    val r2 = typeOf(i.asDynamic().foo())
+    if (r2 != "object") return "fail2: $r2"
+
+    val r3 = typeOf(a.asDynamic().foo())
+    if (r3 != "object") return "fail3: $r3"
+
+    val x4 = b.foo()
+    val r4 = typeOf(x4)
+    if (r4 != "number") return "fail4: $r4"
+
+    val x5 = i.foo()
+    val r5 = typeOf(x5)
+    if (r5 != "object") return "fail5: $r5"
+
+    val x6 = a.foo()
+    val r6 = typeOf(x6)
+    if (r6 != "number") return "fail6: $r6"
+
+    return "OK"
+}

js/js.translator/testData/box/coercion/propertyBridgeChar.kt

@@ -0,0 +1,70 @@
+// EXPECTED_REACHABLE_NODES: 1039
+open class A {
+    val foo: Char
+        get() = 'X'
+
+    var bar: Char = 'Y'
+
+    val baz: Char = 'Q'
+
+    var mutable: Char = 'W'
+        get() {
+            typeOfMutable += typeOf(field.asDynamic()) + ";"
+            return field + 1
+        }
+        set(value) {
+            typeOfMutable += typeOf(js("value")) + ";" + typeOf(value)
+            field = value
+        }
+}
+
+interface I {
+    val foo: Any
+
+    val bar: Any
+
+    val baz: Any
+
+    val mutable: Any
+}
+
+class B : A(), I
+
+fun typeOf(x: dynamic): String = js("typeof x")
+
+var typeOfMutable = ""
+
+fun box(): String {
+    val a = B()
+    val b: I = B()
+
+    val r1 = typeOf(a.foo)
+    if (r1 != "number") return "fail1: $r1"
+
+    val r2 = typeOf(b.foo)
+    if (r2 != "object") return "fail2: $r2"
+
+    val r3 = typeOf(a.asDynamic().foo)
+    if (r3 != "object") return "fail3: $r3"
+
+    val r4 = typeOf(a.asDynamic().bar)
+    if (r4 != "object") return "fail4: $r4"
+
+    val r5 = typeOf(a.asDynamic().baz)
+    if (r5 != "object") return "fail5: $r5"
+
+    a.bar++
+    val r6 = typeOf(a.asDynamic().bar)
+    if (r6 != "object") return "fail6: $r6"
+
+    val r7 = typeOf(a.asDynamic().mutable)
+    if (r7 != "object") return "fail7: $r7"
+
+    a.mutable = 'E'
+    if (typeOfMutable != "number;object;number") return "fail8: $typeOfMutable"
+
+    val r9 = typeOf(a.mutable)
+    if (r9 != "number") return "fail9: $r9"
+
+    return "OK"
+}