added try/catch

Former-commit-id: 5491351bf661dce58b37e8971f8c1d55fd385d13

lib/single-file/modules/css-fonts-alt-minifier.js

@@ -273,7 +273,13 @@ this.singlefile.lib.modules.fontsAltMinifier = this.singlefile.lib.modules.fonts
 		const cssTree = singlefile.lib.vendor.cssTree;
 		let property;
 		if (ruleData.block.children) {
-			property = ruleData.block.children.filter(node => node.property == propertyName && !cssTree.generate(node.value).match(/\\9$/)).tail;
+			property = ruleData.block.children.filter(node => {
+				try {
+					return node.property == propertyName && !cssTree.generate(node.value).match(/\\9$/);
+				} catch (error) {
+					// ignored
+				}
+			}).tail;
 		}
 		if (property) {
 			try {