Optimize the KLoggerNameResolver for jvm

[scrat98]

Part 1 of #480

Optimize the KLoggerNameResolver for jvm, since we don't need to search indexOf multiple times.

[scrat98]

@oshai Also please note, that KLoggerNameResolver::name(func: () -> Unit) is never used in the tests. Therefore I'm not sure should we apply the same logic for name(forClass: Class<T>). To do the following:

  /** get class name for function by the package of the function */
  internal actual fun name(func: () -> Unit): String {
    return name(func::class)
  }

  /** get class name for java class (that usually represents kotlin class) */
  internal fun name(clazz: KClass<*>): String {
    return clazz.java.name.toCleanClassName()
  }

The problem with that tests rely on the old behavior (with enclosingClass reflection), for example:

      Arguments.of(
        "io.github.oshai.kotlinlogging.internal.BaseClass\$InnerClass\$Obj",
        BaseClass.InnerClass.Obj::class.java,
      )