Fix JVM signatures involving multi-dimensional array types

Apparently ASM's Type#getElementType returns the type of the array even if it's
multi-dimensional, so the loop was incorrect

compiler/testData/codegen/boxWithStdlib/reflection/properties/propertyOfNestedClassAndArrayType.kt

@@ -0,0 +1,16 @@
+class A {
+    class B(val result: String)
+
+    var p: A.B? = null
+    var q: Array<Array<A.B>>? = null
+}
+
+fun box(): String {
+    val a = A()
+
+    (A::q).set(a, array(array(A.B("array"))))
+    if (a.q!![0][0].result != "array") return "Fail array"
+
+    (A::p).set(a, A.B("OK"))
+    return a.p!!.result
+}