Generate bridges for trait implementations properly

The intent was to keep the bridge codegen model as simple as possible: we
should be able to figure out all necessary bridges only by a minimal interface
that FunctionHandle provides (isAbstract, isDeclaration, getOverridden)

Add different tests for bridges

 #KT-318 Obsolete

compiler/testData/codegen/box/bridges/complexTraitImpl.kt

@@ -0,0 +1,28 @@
+import java.util.ArrayList
+import java.util.Arrays
+
+abstract class A {
+    abstract fun foo(): List<String>
+}
+
+trait B {
+    fun foo(): ArrayList<String> = ArrayList(Arrays.asList("B"))
+}
+
+open class C : A(), B
+
+trait D {
+    fun foo(): Collection<String>
+}
+
+class E : D, C()
+
+fun box(): String {
+    val e = E()
+    var r = e.foo()[0]
+    r += (e : D).foo().iterator().next()
+    r += (e : C).foo()[0]
+    r += (e : B).foo()[0]
+    r += (e : A).foo()[0]
+    return if (r == "BBBBB") "OK" else "Fail: $r"
+}

compiler/testData/codegen/box/bridges/fakeOverrideInTraitWithRequiredFromTraitImpl.kt

@@ -0,0 +1,17 @@
+abstract class A {
+    abstract fun foo(): Any
+}
+
+trait B {
+    fun foo(): String = "B"
+}
+
+trait C : A, B
+
+class D : A(), C
+
+fun box(): String {
+    val d = D()
+    val r = d.foo() + (d : C).foo() + (d : B).foo() + (d : A).foo()
+    return if (r == "BBBB") "OK" else "Fail: $r"
+}

compiler/testData/codegen/box/bridges/fakeOverrideOfPropertySetterInTraitImpl.kt

@@ -0,0 +1,23 @@
+var result = ""
+
+trait A {
+    var foo: String
+        get() = result
+        set(value) {
+            result += value
+        }
+}
+
+abstract class B {
+    abstract var foo: Any
+}
+
+class C : A, B()
+
+fun box(): String {
+    val c = C()
+    c.foo = "1"
+    (c : B).foo = "2"
+    (c : A).foo = "3"
+    return if (result == "123") "OK" else "Fail: $result"
+}

compiler/testData/codegen/box/bridges/fakeOverrideWithImplementationInTrait.kt

@@ -0,0 +1,18 @@
+trait A {
+    fun foo(): String = "A"
+}
+
+trait B {
+    fun foo(): Any
+}
+
+class C : A, B
+
+fun box(): String {
+    val c = C()
+    var result = ""
+    result += c.foo()
+    result += (c : B).foo()
+    result += (c : A).foo()
+    return if (result == "AAA") "OK" else "Fail: $result"
+}

compiler/testData/codegen/box/bridges/kt318.kt

@@ -0,0 +1,23 @@
+var result = ""
+
+trait Base
+open class Child : Base
+
+trait A<T : Base> {
+    fun <E : T> foo(a : E) {
+        result += "A"
+    }
+}
+
+class B : A<Child> {
+    override fun <E : Child> foo(a : E) {
+        result += "B"
+    }
+}
+
+fun box(): String {
+    val b = B()
+    b.foo(Child())
+    (b : A<Child>).foo(Child())
+    return if (result == "BB") "OK" else "Fail: $result"
+}

compiler/testData/codegen/box/bridges/noBridgeOnMutableCollectionInheritance.kt

@@ -0,0 +1,22 @@
+import java.util.ArrayList
+import java.util.Arrays
+
+trait A {
+    fun foo(): Collection<String>
+}
+
+trait B : A {
+    override fun foo(): MutableCollection<String>
+}
+
+class C : B {
+    override fun foo(): MutableList<String> = ArrayList(Arrays.asList("C"))
+}
+
+fun box(): String {
+    val c = C()
+    var r = c.foo().iterator().next()
+    r += (c : B).foo().iterator().next()
+    r += (c : A).foo().iterator().next()
+    return if (r == "CCC") "OK" else "Fail: $r"
+}

compiler/testData/codegen/box/bridges/traitImplInheritsTraitImpl.kt

@@ -0,0 +1,15 @@
+trait A {
+    fun foo(): Any = "A"
+}
+
+trait B : A {
+    override fun foo(): String = "B"
+}
+
+class C : B
+
+fun box(): String {
+    val c = C()
+    var r = c.foo() + (c : B).foo() + (c : A).foo()
+    return if (r == "BBB") "OK" else "Fail: $r"
+}

compiler/testData/codegen/box/bridges/traitWithRequiredCovariantOverride.kt

@@ -0,0 +1,15 @@
+open class A {
+    open fun foo(): Any = "A"
+}
+
+trait B : A {
+    override fun foo(): String = "B"
+}
+
+class C : A(), B
+
+fun box(): String {
+    val c = C()
+    val r = c.foo() + (c : B).foo() + (c : A).foo()
+    return if (r == "BBB") "OK" else "Fail: $r"
+}