Do not create Array instance in kotlin-reflect where not necessary

Although the previous code of computing JVM internal name from a Class
instance was shorter, it led to unnecessary creation of array types,
which is less performant and makes configuration of kotlin-reflect for
GraalVM native-image more verbose.

Unfortunately I didn't succeed in writing a test for this, since
`Array.newInstance` calls a native method which doesn't record any trace
of it being called in the class loader: the resulting array type never
goes through findClass/loadClass, and is not visible via
findLoadedClass.

 #KT-44594 Fixed

core/descriptors.runtime/src/org/jetbrains/kotlin/descriptors/runtime/structure/reflectClassUtil.kt

@@ -67,16 +67,23 @@ val Class<*>.classId: ClassId
     }
 
 val Class<*>.desc: String
-    get() {
-        if (this == Void.TYPE) return "V"
-        // This is a clever exploitation of a format returned by Class.getName(): for arrays, it's almost an internal name,
-        // but with '.' instead of '/'
-        return createArrayType().name.substring(1).replace('.', '/')
+    get() = when {
+        isPrimitive -> when (name) {
+            "boolean" -> "Z"
+            "char" -> "C"
+            "byte" -> "B"
+            "short" -> "S"
+            "int" -> "I"
+            "float" -> "F"
+            "long" -> "J"
+            "double" -> "D"
+            "void" -> "V"
+            else -> throw IllegalArgumentException("Unsupported primitive type: $this")
+        }
+        isArray -> name.replace('.', '/')
+        else -> "L${name.replace('.', '/')};"
     }
 
-fun Class<*>.createArrayType(): Class<*> =
-    Array.newInstance(this, 0)::class.java
-
 /**
  * @return all arguments of a parameterized type, including those of outer classes in case this type represents an inner generic.
  * The returned list starts with the arguments to the innermost class, then continues with those of its outer class, and so on.