Style tag loading is very slow for a large number of style tags
Svgs and other files typically open nicely with my Inkscape 1.0beta2, but I have two svgs that I have made myself with 0.92 that does not open and makes Inkscape hang. They both open fine in 0.92 and with Affinity.
I tried removing all the contents of the file and did a clean up document with 0.92 to see if it would then open in 1.0, but still no luck.
#### Steps to reproduce:
- open the attached file from Finder
or
- open from command line (with or without gui)
#### What happened?
Inkscape process is spawned, quickly hoards memory (8GB and counting) and shows up as not responding in activity monitor. I force quit after a while.
In the command line I get
```
(process:2316): Gtk-WARNING **: 11:05:30.122: Locale not supported by C library.
Using the fallback 'C' locale.
Pango version: 1.43.0
```
then the process accumulates GBs of memory (to open a 15KB file) until I sigterm it.
#### What should have happened?
The file should have opened normally as it does in 0.92 and other svg editing software.
#### Inkscape Version and Operating System:
- Inkscape Version: Inkscape 1.0beta2 (2b71d25, 2019-12-03)
- Operating System: macOS
- Operating System version: 10.14.6
Attached (empty) svg:

issue