Fix undefined maxFontSize
Fix undefined maxFontSize

Fix getting a NaN maxFontSize in makeVList because symbolNodes don't have a
maxFontSize property.

Test plan:
 - Make sure no huxley screenshots changed

Auditors: alpert

kwangkim/KaTeX,zhanghuiguoanlige/KaTeX,spicyj/KaTeX,azotova/KaTeX,franciscop/KaTeX,gagern/KaTeX,frankandrobot/KaTeX,JetStarBlues/KaTeX,spicyj/KaTeX,xymostech/KaTeX,frankandrobot/KaTeX,kwangkim/katex-npm-0.7.0-pre,spicyj/KaTeX,saschatimme/KaTeX,Khan/KaTeX,Khan/KaTeX,xymostech/KaTeX,mcanthony/KaTeX,kevinbarabash/KaTeX,kevinbarabash/KaTeX,franciscop/KaTeX,kwangkim/KaTeX,mcanthony/KaTeX,azotova/KaTeX,azotova/KaTeX,kwangkim/KaTeX,zhanghuiguoanlige/KaTeX,JetStarBlues/KaTeX,saschatimme/KaTeX,saschatimme/KaTeX,kwangkim/KaTeX,crepererum/KaTeX,saschatimme/KaTeX,kevinbarabash/KaTeX,franciscop/KaTeX,mcanthony/KaTeX,kwangkim/katex-npm-0.7.0-pre,azotova/KaTeX,kwangkim/katex-npm-0.7.0-pre,twitwi/KaTeX,gagern/KaTeX,crepererum/KaTeX,frankandrobot/KaTeX,JetStarBlues/KaTeX,gagern/KaTeX,zhanghuiguoanlige/KaTeX,crepererum/KaTeX,kwangkim/katex-npm-0.7.0-pre,saschatimme/KaTeX,twitwi/KaTeX,zhanghuiguoanlige/KaTeX,franciscop/KaTeX,franciscop/KaTeX,JetStarBlues/KaTeX,kevinbarabash/KaTeX,spicyj/KaTeX,zhanghuiguoanlige/KaTeX,spicyj/KaTeX,xymostech/KaTeX,mcanthony/KaTeX,twitwi/KaTeX,crepererum/KaTeX,mcanthony/KaTeX,JetStarBlues/KaTeX,kevinbarabash/KaTeX,gagern/KaTeX,twitwi/KaTeX,twitwi/KaTeX,kwangkim/katex-npm-0.7.0-pre,azotova/KaTeX,frankandrobot/KaTeX,frankandrobot/KaTeX,gagern/KaTeX,crepererum/KaTeX,xymostech/KaTeX,Khan/KaTeX,kwangkim/KaTeX,xymostech/KaTeX