Biber parsing problem with abstracts and the = symbol

[hvoss49]

An abstract with a "=" character in the second or later line is parsed incorrectly.

voss>Rich:$ cat test.bib
@article{Cade2006,
	abstract = {foo 
	            x = 1 bar},
	author = {Cade, B.S.},
	journal = {Journal of Agricultural, Biological, and Environmental Statistics},
	number = {1},
	pages = {106–126},
	title = {{A Permutation Test for Quantile Regressio}},
	volume = {11},
	year = {2006}
}

The output with up-to-date TL23 installation:

voss>Rich:$ biber --tool test.bib 
INFO - This is Biber 2.19 running in TOOL mode
INFO - Logfile is 'test.bib.blg'
INFO - Looking for bibtex file 'test.bib'
INFO - LaTeX decoding ...
INFO - Found BibTeX data source 'test.bib'
INFO - Overriding locale 'en_US' defaults 'variable = shifted' with 'variable = non-ignorable'
INFO - Overriding locale 'en_US' defaults 'normalization = NFD' with 'normalization = prenormalized'
INFO - Sorting list 'tool/global//global/global' of type 'entry' with template 'tool' and locale 'en_US'
INFO - No sort tailoring available for locale 'en_US'
INFO - Writing 'test_bibertool.bib' with encoding 'UTF-8'
INFO - Output to test_bibertool.bib
WARN - BibTeX subsystem: /var/folders/46/kr8jdrld7d324jpscgrlw2fh0000gn/T/biber_tmp_2X6Y/5a453152acdb3e2485a9d6a17b3ec69c_39406.utf8, line 8, warning: possible runaway string started at line 2
INFO - WARNINGS: 1

Using (x = 1) or {x = 1}. will be okay.

[plk]

Fixing this is going to mean hacking the ancient btparse C library unfortunately - this is an edge case and so I doubt it will be looked at in the near future, sorry.