Retain the casing in map files in file names

Author: sheetalkamat

src/compiler/sourcemapDecoder.ts

@@ -83,7 +83,7 @@ namespace ts.sourcemaps {
             if (!maps[targetIndex] || comparePaths(loc.fileName, maps[targetIndex].sourcePath, sourceRoot, !host.useCaseSensitiveFileNames) !== 0) {
                 return loc;
             }
-            return { fileName: toPath(map.file!, sourceRoot, host.getCanonicalFileName), position: maps[targetIndex].emittedPosition }; // Closest pos
+            return { fileName: getNormalizedAbsolutePath(map.file!, sourceRoot), position: maps[targetIndex].emittedPosition }; // Closest pos
         }
 
         function getOriginalPosition(loc: SourceMappableLocation): SourceMappableLocation {
@@ -94,7 +94,7 @@ namespace ts.sourcemaps {
                 // if no exact match, closest is 2's compliment of result
                 targetIndex = ~targetIndex;
             }
-            return { fileName: toPath(maps[targetIndex].sourcePath, sourceRoot, host.getCanonicalFileName), position: maps[targetIndex].sourcePosition }; // Closest pos
+            return { fileName: getNormalizedAbsolutePath(maps[targetIndex].sourcePath, sourceRoot), position: maps[targetIndex].sourcePosition }; // Closest pos
         }
 
         function getSourceFileLike(fileName: string, location: string): SourceFileLike | undefined {

src/testRunner/unittests/tsserverProjectSystem.ts

@@ -10655,7 +10655,7 @@ declare class TestLib {
             const dependecyLocation = `${projectLocation}/dependency`;
             const mainLocation = `${projectLocation}/main`;
             const dependencyTs: File = {
-                path: `${dependecyLocation}/fns.ts`,
+                path: `${dependecyLocation}/FnS.ts`,
                 content: `export function fn1() { }
 export function fn2() { }
 export function fn3() { }