fix(@angular-devkit/core): Windows path normalize bug

The Windows drive letter could be lower case.

This PR fix angular/angular-cli#10328

Author: doggy8088

packages/angular_devkit/core/src/virtual-fs/path.ts

@@ -204,7 +204,7 @@ export function normalize(path: string): Path {
 
   // Match absolute windows path.
   const original = path;
-  if (path.match(/^[A-Z]:[\/\\]/)) {
+  if (path.match(/^[A-Z]:[\/\\]/i)) {
     path = '\\' + path[0] + '\\' + path.substr(3);
   }
 

packages/angular_devkit/core/src/virtual-fs/path_spec.ts

@@ -70,6 +70,7 @@ describe('path', () => {
     expect(normalize('\\a\\b\\c')).toBe('/a/b/c');
     expect(normalize('.\\a\\b\\c')).toBe('a/b/c');
     expect(normalize('C:\\a\\b\\c')).toBe('/C/a/b/c');
+    expect(normalize('c:\\a\\b\\c')).toBe('/c/a/b/c');
     expect(normalize('A:\\a\\b\\c')).toBe('/A/a/b/c');
     expect(() => normalize('A:\\..\\..'))
       .toThrow(new InvalidPathException('A:\\..\\..'));