fixed microsoft#173858 minimap slider not scrolling to the top end (microsoft#180728)

fixed div/0 in minimap slider position calculation

also execute if block if scrollTop equals options.paddingTop
this avoids div/0 in else block when options.paddingTop is 0

Author: Dromantor

src/vs/editor/browser/viewParts/minimap/minimap.ts

@@ -377,7 +377,7 @@ class MinimapLayout {
 			const partialLine = (scrollTop - viewportStartLineNumberVerticalOffset) / lineHeight;
 
 			let sliderTopAligned: number;
-			if (scrollTop > options.paddingTop) {
+			if (scrollTop >= options.paddingTop) {
 				sliderTopAligned = (viewportStartLineNumber - startLineNumber + topPaddingLineCount + partialLine) * minimapLineHeight / pixelRatio;
 			} else {
 				sliderTopAligned = (scrollTop / options.paddingTop) * (topPaddingLineCount + partialLine) * minimapLineHeight / pixelRatio;