test(math): Upgrade math tests that were relying on the font size

These tests use document font size at 11pt, but formulas would be
typeset at 10pt as the math.font.size default was hard-coded.
It now follows the current document font size, so enforce it back
to 10pt in order for the test to pass unchanged.

tests/feat-math-display-numbered.sil

@@ -4,6 +4,11 @@
 \use[module=packages.lorem]
 \use[module=packages.math]
 \font[size=11pt]
+% Side effect of #2145: the math font size now follow the current document
+% font size, so whould now be 11pt.
+% The previous behavior was an hard-coded 10 pt.
+% Restore it here, so the test passes unchanged.
+\set[parameter=math.font.size, value=10]
 % Test numbered display math for all options
 % and in all alignments
 

tests/feat-math-display-unnumbered.sil

@@ -9,6 +9,11 @@
 % and in all alignments
 
 \begin{blockquote}
+% Side effect of #2145: the math font size now follow the current document
+% font size, so whould now be some ratio of 11pt (due to the blockquote)
+% The previous behavior was an hard-coded 10 pt.
+% Restore it here, so the test passes unchanged.
+\set[parameter=math.font.size, value=10]
 Begin justified
 \math[mode=display]{e^{i\pi} = -1}
 End justified.