crashtesting: many asserts in SmTextNode::Prepare

e.g fdo58094-1.mml

since...

commit 13894996
Date:   Sat May 4 21:46:31 2019 +0200

    handle empty Rectangle better in starmath

Change-Id: I01d11352b8bc9f6dcf6d6565fa41b84d549f620f
Reviewed-on: https://gerrit.libreoffice.org/71963
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>

starmath/source/node.cxx

@@ -2064,7 +2064,6 @@ void SmTextNode::Prepare(const SmFormat &rFormat, const SmDocShell &rDocShell, i
         SetRectHorAlign( RectHorAlign::Left );
 
     maText = GetToken().aText;
-    assert(!maText.isEmpty());
     GetFont() = rFormat.GetFont(GetFontDesc());
 
     if (IsItalic( GetFont() ))

starmath/source/rect.cxx

@@ -38,7 +38,6 @@ bool SmGetGlyphBoundRect(const vcl::RenderContext &rDev,
     // basically the same as 'GetTextBoundRect' (in class 'OutputDevice')
     // but with a string as argument.
 {
-    assert(!rText.isEmpty());
     // handle special case first
     if (rText.isEmpty())
     {
@@ -184,7 +183,6 @@ SmRect::SmRect(const OutputDevice &rDev, const SmFormat *pFormat,
     : aTopLeft(0, 0)
     , aSize(rDev.GetTextWidth(rText), rDev.GetTextHeight())
 {
-    assert(!rText.isEmpty());
     const FontMetric  aFM (rDev.GetFontMetric());
     bool              bIsMath  = aFM.GetFamilyName().equalsIgnoreAsciiCase( FONTNAME_MATH );
     bool              bAllowSmaller = bIsMath && !SmIsMathAlpha(rText);