Problem:  Strange error when heredoc marker starts with "trim".
Solution: Check for whitespace after "trim" or "eval" (zeertzjq)

For :python3 etc., a heredoc marker that starts with a lower-case letter
is valid, and when it starts with "trim" it works in a script but not in
a function, and this PR makes it works in a function.
For :let, a heredoc marker that starts with a lower-case letter is not
valid, but when it starts with "trim" or "eval" the error can be a bit
confusing in a function, and this PR make it less confusing.

closes: vim/vim#16574

https://github.com/vim/vim/commit/449c2e5454735fe1cfc8c21b2c6880d6bdf4cd6e

Problem:  tests: ruby tests fail with Ruby 3.4
Solution: adjust expected output for Ruby 3.4
          (Yee Cheng Chin)

Vim's Ruby tests relied on explicit matching of output texts which are
fragile in design. Ruby 3.4 has changed the output slightly (using
'name' instead of `name', and also using more spaces in dictionary
printouts). Modify the Vim tests to be less fragile to such changes.

closes: vim/vim#16411

https://github.com/vim/vim/commit/ebea31e454b9a1731cde845226f2c28ca5c097b1

Co-authored-by: Yee Cheng Chin <ychin.git@gmail.com>

Problem:  Cannot build against Ruby 33 dynamically
Solution: Ruby 33 removed transient heap, so do not use
          rb_ary_transient anymore, NoMethodError format changed,
          so update test for expected error message
          (Isao Sato)

- ruby-3.3 removed transient heap for ruby/dyn

when +ruby/dyn with ruby-3.3 do command :ruby, E448 occur.
ruby-3.3 has no transient heap anymore, so disable rb_ary_transient etc.

$ LC_ALL=C VIMRUNTIME=runtime ./src/vim -u NONE -c 'ruby puts RUBY_VERSION'
"=> Error detected while processing command line:
"=> E448: Could not load library function rb_ary_detransient
"=> E266: Sorry, this command is disabled, the Ruby library could not be
    loaded.

- ruby-3.3 changed NoMethodError format:

$ rvm 3.2.2, 3.3.0-rc1 do ruby -e 'begin; nil.name; rescue => e; puts "%s : %s"%[RUBY_VERSION, e.message]; end '
=> 3.2.2 : undefined method `name' for nil:NilClass
=> 3.3.0 : undefined method `name' for nil

so loose pattern in Test_ruby_Vim_buffer_get()

closes: vim/vim#13741

https://github.com/vim/vim/commit/443657b32becb2318ae40e30a849bbe5cc1a153c

Co-authored-by: Isao Sato <svardew@gmail.com>

Problem:    Tests fail when the float feature is disabled.
Solution:   Skip tests that don't work without float support.

https://github.com/vim/vim/commit/5feabe00c47fa66d5f4c95213f150488433f78e3

Cherry-pick Test_ruby_Vim_blob() from patch 8.1.0977 and skip it.

Co-authored-by: Bram Moolenaar <Bram@vim.org>

Problem:    Heredoc in scripts does not accept lower case marker.
Solution:   Allow lower case only in non-Vim scripts. (Ken Takata,
            closes vim/vim#6019)

https://github.com/vim/vim/commit/6ab0953fefe31fef91e40752a675ceb60fc2fe03

Problem:    Heredoc for interfaces does not support "trim".
Solution:   Update the script heredoc support to be same as the :let command.
            (Yegappan Lakshmanan, closes vim/vim#5916)

https://github.com/vim/vim/commit/6c2b7b8055b96463f78abb70f58c4c6d6d4b9d55

The new oldtest directory is in test/old/testdir. The reason for this is
that many tests have hardcoded the parent directory name to be
'testdir'.