[Bug #21144] Win32: Use Windows time zone ID if TZ is not set

	If the TZ environment variable is not set, the time zone names
	retrieved from the system are localized for UI display and may vary
	across editions and language packs for the same time zone.
	Use the time zone IDs that are invariant across environments instead.

	[Bug #21144] Win32: Convert the time zone name to the current locale

	The Windows time zone IDs provided by Microsoft as of 24H1 are ASCII
	only all, but the API itself is not impossible to set non-ASCII key
	name.  Prefer the current locale encoding for now until we move to
	UTF-8 including environment variables and command line arguments.

	[Bug #20984] ENV.inspect should be encoding aware

	[Bug #20984] Fix test with locale encoding

	[Bug #20307] Fix `Hash#update` to make frozen copy of string keys

Merged into master in 7ba2506232d3fa6c4e82e3708c0ff746a1a8de5c

[Bug #20050]

	[Bug #19969] Compact st_table after deleted if possible

	---
	 hash.c                 | 19 +++++++++++++++++++
	 st.c                   | 40 +++++++++++++++++++++++++++++-----------
	 test/ruby/test_hash.rb |  9 +++++++++
	 3 files changed, 57 insertions(+), 11 deletions(-)

	hash.c: Fix hash_iter_lev_dec corrupting shape

	[Bug #19589]

	When decrementing `iter_lev` from `65` to `64` the flags would be
	corrupted, causing the shape_id to be invalid.
	---
	 hash.c                 | 12 +++++++++---
	 test/ruby/test_hash.rb | 11 +++++++++++
	 2 files changed, 20 insertions(+), 3 deletions(-)