[GR-60649] [GR-61423] Various fixes for system properties and locales.

[graalvmbot]

• Fixed crashes related to the locale support.
• Fixed memory leaks in the locale support.
• Added proper error handling to the locale C implementation.
• Refactored the locale-related interface between Java and C.
• Added a proper @CStruct for LocaleProps (before, we wrongly assumed that the C compiler needs to use a certain layout for the struct)
• Fixed the #ifdefs in locale.c so that more code is excluded on Windows.
• Fixed various issues where the locale support in Native Image would behave differently from the one in HotSpot (especially related to the defaulting logic in SystemProps.fillI18nProps(...)).
• The locale support is now only initialized once per process (instead of multiple times per isolate).
• Disabled locale support for libgraal (see option UseSystemLocale).
• Deprecated the API function ProcessProperties.setLocale(...) as it is inherently unsafe.
• Fixed incomplete @BasedOnJDKFile annotations for the locale support.
• Fixed various issues where we initialized all lazy system properties even though only a single system property was requested.
• Fixed various race conditions in SystemPropertiesSupport.
• Fixed a ConcurrentModificationException in the SystemPropertiesSupport that could happen with multi-threading.
• Fixed user.region handling in Target_jdk_internal_util_StaticProperty.
• Fixed Target_jdk_internal_util_StaticProperty.USER_LANGUAGE_FORMAT which contained a wrong value.
• Fixed Target_jdk_internal_util_StaticProperty.javaHome(), osName(), osArch(), and osVersion().
• Fixed the value of the system property os.arch on Darwin.
• Marked all fields that should not be reachable at runtime with @Delete in Target_jdk_internal_util_StaticProperty (they contain problematic hosted values).
• Removed some no longer needed code (leftover from JDK 11).