Fix stroke behind fill in PDF export

The three text passes in the most inner loop causes issues when the stroke is supposed to be behind the fill. Instead of painting the stroke and fill together per glyph block, we instead paint the stroke first and request a second pass to conclude the fill.

Fixes #4219 (closed)

Tests added (cli-text export-text-paintorder):

• Fill and Stroke, Fill First
• Fill and Stroke, Stroke First
• Fill only, Fill First
• Fill only, Stroke First
• Stroke only, Fill First
• Stroke only, Stroke First
• No stroke or fill (invisible)
• Tests pass locally