Address failures of Seminar examples on new TL20

Compilation of our Seminar example file fails on updated TL20. The
maintainer of "Seminar" is not planning to fix the core issue and
states the following (in a private email with permission to quote):

  it is a problem with the new hook management of the current latex.ltx
  seminar is a quite old package and there is no reason to use it with a
  new LaTeX format. It won't be fixed, so the usual way is to use the
  package latexrealease to get the old hook management.

This commit adds a note to the example files explaining the
workaround of exporting to a .tex file and prepending the following
line:

  \RequirePackage[2020-02-02]{latexrelease}

We now invert the relevant tests.

development/autotests/invertedTests

@@ -336,6 +336,11 @@ export/export/latex/languages/uk-babel-date-missing-chars-with-ascii_pdf5_texF
 # Reported here and there is hope for a fix soon.
 # https://github.com/tweh/menukeys/issues/59
 export/export/latex/unicodesymbols/07[48]-.*
+# These fail for perhaps a similar reason, but contrary to the unicodesymbols
+# case the maintainer of the seminar package is not planning to fix the core
+# issue since the package is old. Putting the following as the first line of
+# the LaTeX file is a workaround: \RequirePackage[2020-02-02]{latexrelease}
+export/examples/(fr/|)Presentations/Seminar.*(dvi|pdf|lyx22|lyx23).*
 
 
 # ================================================

lib/examples/Presentations/Seminar.lyx

@@ -1,4 +1,4 @@
-#LyX 2.4 created this file. For more info see https://www.lyx.org/
+#LyX 2.3 created this file. For more info see http://www.lyx.org/
 \lyxformat 544
 \begin_document
 \begin_header
@@ -92,6 +92,32 @@
 
 \begin_body
 
+\begin_layout Standard
+\begin_inset Note Note
+status open
+
+\begin_layout Plain Layout
+Compilation of this example fails on updated TeX Live 2020.
+ The smaintainer of the 
+\begin_inset Quotes eld
+\end_inset
+
+seminar
+\begin_inset Quotes erd
+\end_inset
+
+ package is not planning to fix the core issue since the package is old.
+ A workaround is to export to .tex and prepend as the first line the following:
+ 
+\backslash
+RequirePackage[2020-02-02]{latexrelease}
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
 \begin_layout Standard
 \begin_inset Flex LandscapeSlide
 status open

lib/examples/fr/Presentations/Seminar.lyx

@@ -1,4 +1,4 @@
-#LyX 2.4 created this file. For more info see https://www.lyx.org/
+#LyX 2.3 created this file. For more info see http://www.lyx.org/
 \lyxformat 544
 \begin_document
 \begin_header
@@ -102,6 +102,27 @@
 
 \begin_body
 
+\begin_layout Standard
+\begin_inset Note Note
+status open
+
+\begin_layout Plain Layout
+
+\lang english
+Compilation of this example fails on updated TeX Live 2020.
+ The smaintainer of the “seminar” package is not planning to fix the core
+ issue since the package is old.
+ A workaround is to export to .tex and prepend as the first line the following:
+ 
+\backslash
+RequirePackage[2020-02-02]{latexrelease}
+\end_layout
+
+\end_inset
+
+
+\end_layout
+
 \begin_layout Standard
 \begin_inset Flex LandscapeSlide
 status open