[K/N] Make classes generated from λs that use generic parameters generic

Previously, a function reference that used generic parameters from its
outer scope was lowered into a top-level non-generic subclass of
`FunctionN`, with `FunctionN` type arguments referencing type parameters
not present in the scope anymore. This sometimes resulted in generating
malformed mangled names.

From now on the generated subclass of `FunctionN` is generic. The needed
type arguments are passed upon instantiation, when the relevant generic
parameters are present in the scope.

compiler/testData/codegen/box/closures/closureCapturingGenericParam.kt

@@ -0,0 +1,20 @@
+interface IntConvertible {
+    fun toInt(): Int
+}
+
+fun <FooTP> foo(init: Int, v: FooTP, l: Int.(FooTP) -> Int) = init.l(v)
+
+fun <BarTP : IntConvertible> computeSum(array: Array<BarTP>) = foo(0, array) {
+    var res = this
+    for (element in it) res += element.toInt()
+    res
+}
+
+class N(val v: Int) : IntConvertible {
+    override fun toInt() = v
+}
+
+fun box(): String {
+    if (computeSum(arrayOf(N(2), N(14))) != 16) return "Fail"
+    return "OK"
+}