Fix 'completion-ignore-case' with 'completion--file-name-table'

Fix 'completion-ignore-case' with 'completion--file-name-table'

509cbe1c35b3d "Improve env var handling in read-file-name"
caused 'try-completion' and 'all-completion' operations with
'completion--file-name-table' to no longer update the case of
text which was already present in the input string.  That is,
completions would be returned ignoring case, but the completions
would have letter-casing which matched the input string rather
than matching the actual file names.
This was caused by unnecessarily replacing text in the returned
file name completions with text from the input string ORIG,
which in turn was caused by the desire to preserve text from
ORIG even after 'substitute-in-file-name' changed it.  Fix this
by detecting when ORIG was not substantially changed by
'substitute-in-file-name'; in that case, the returned file name
completions also don't need substantial changes.
* lisp/minibuffer.el (completion--file-name-table): Use text
from the completions, not the input string.  (Bug#78323)
* test/lisp/minibuffer-tests.el (completion-table-test-quoting):
Test with 'completion-ignore-case' as well.

(cherry picked from commit cd364a2119b81f58e0d8f6579809dceb86a8f63c)