Revert "Fixes microsoft#94144: Remove special dark theme cursor"

This reverts commit a915df1.

The special macOS dark cursor is still useful for users stuck on older
versions of macOS. Even on macOS Catalina, this cursor is helpful for
reducing visual bloat.

src/vs/editor/browser/viewParts/lines/viewLines.css

@@ -27,6 +27,11 @@
 	white-space: nowrap;
 }
 
+.monaco-editor.vs-dark.mac .view-lines,
+.monaco-editor.hc-black.mac .view-lines {
+	cursor: -webkit-image-set(url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAQAAAC1+jfqAAAAL0lEQVQoz2NgCD3x//9/BhBYBWdhgFVAiVW4JBFKGIa4AqD0//9D3pt4I4tAdAMAHTQ/j5Zom30AAAAASUVORK5CYII=') 1x, url('data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAACAAAAAgCAQAAADZc7J/AAAAz0lEQVRIx2NgYGBY/R8I/vx5eelX3n82IJ9FxGf6tksvf/8FiTMQAcAGQMDvSwu09abffY8QYSAScNk45G198eX//yev73/4///701eh//kZSARckrNBRvz//+8+6ZohwCzjGNjdgQxkAg7B9WADeBjIBqtJCbhRA0YNoIkBSNmaPEMoNmA0FkYNoFKhapJ6FGyAH3nauaSmPfwI0v/3OukVi0CIZ+F25KrtYcx/CTIy0e+rC7R1Z4KMICVTQQ14feVXIbR695u14+Ir4gwAAD49E54wc1kWAAAAAElFTkSuQmCC') 2x) 5 8, text;
+}
+
 .monaco-editor .view-line {
 	position: absolute;
 	width: 100%;