implemented IcuFontFromServerFont::getFontTable(LETag,size_t&)

so that ICU versions trying to call
LEFontInstance::getFontTable(LETag,size_t&) actually call it instead of
IcuFontFromServerFont::getFontTable(LETag)

See http://site.icu-project.org/download/51#TOC-Known-Issues
"NOTE: Applications must implement LEFontInstance::getFontTable(LETag,
size_t &length)  in their LEFontInstance subclasses, so that ICU can
properly bounds-check font tables."

See also https://ssl.icu-project.org/trac/ticket/10107

Change-Id: Ic20b7e8dda4e84734eb6de0ccba82b0dea481d55

vcl/generic/glyphs/gcach_layout.cxx

@@ -556,6 +556,7 @@ public:
                             {}
 
     using LEFontInstance::getFontTable;
+    virtual const void*     getFontTable(LETag tableTag, size_t &length) const;
     virtual const void*     getFontTable(LETag tableTag) const;
     virtual le_int32        getUnitsPerEM() const;
     virtual float           getXPixelsPerEm() const;
@@ -577,7 +578,7 @@ public:
 
 // -----------------------------------------------------------------------
 
-const void* IcuFontFromServerFont::getFontTable( LETag nICUTableTag ) const
+const void* IcuFontFromServerFont::getFontTable( LETag nICUTableTag, size_t & rLength ) const
 {
     char pTagName[5];
     pTagName[0] = (char)(nICUTableTag >> 24);
@@ -586,9 +587,10 @@ const void* IcuFontFromServerFont::getFontTable( LETag nICUTableTag ) const
     pTagName[3] = (char)(nICUTableTag);
     pTagName[4] = 0;
 
-    sal_uLong nLength;
+    sal_uLong nLength = 0;
     const unsigned char* pBuffer = mrServerFont.GetTable( pTagName, &nLength );
-    SAL_INFO("vcl", "IcuGetTable(\"" << pTagName << "\") => " << pBuffer);
+    rLength = static_cast<size_t>(nLength);
+    SAL_INFO("vcl", "IcuGetTable(\"" << pTagName << "\") => " << pBuffer << ", len=" << rLength);
     SAL_INFO(
         "vcl",
         "font( h=" << mrServerFont.GetFontSelData().mnHeight << ", \""
@@ -596,6 +598,12 @@ const void* IcuFontFromServerFont::getFontTable( LETag nICUTableTag ) const
     return pBuffer;
 }
 
+const void* IcuFontFromServerFont::getFontTable( LETag nICUTableTag ) const
+{
+    size_t nLength = 0;
+    return getFontTable( nICUTableTag, nLength);
+}
+
 // -----------------------------------------------------------------------
 
 le_int32 IcuFontFromServerFont::getUnitsPerEM() const