Revert "fix(compiler-cli): fix case-sensitivity issues in NgtscCompil…

…erHost (#36968)" (#37003)

This reverts commit 4abd603.

The changes to the case-sensitivity handling in #36968 caused multiple
projects to fail to build. See #36992, #36993 and #37000.

The issue is related to the logical path handling. But it is felt that
it is safer to revert the entire PR and then to investigate further.

PR Close #37003

packages/compiler-cli/src/ngtsc/file_system/src/compiler_host.ts

@@ -44,7 +44,7 @@ export class NgtscCompilerHost implements ts.CompilerHost {
   }
 
   getCanonicalFileName(fileName: string): string {
-    return this.useCaseSensitiveFileNames() ? fileName : fileName.toLowerCase();
+    return this.useCaseSensitiveFileNames ? fileName : fileName.toLowerCase();
   }
 
   useCaseSensitiveFileNames(): boolean {

packages/compiler-cli/src/ngtsc/file_system/test/compiler_host_spec.ts

@@ -41,27 +41,5 @@ runInEachFileSystem(() => {
         expect(host.getSourceFile(directory, ts.ScriptTarget.ES2015)).toBe(undefined);
       });
     });
-
-    describe('useCaseSensitiveFileNames()', () => {
-      it('should return the same as `FileSystem.isCaseSensitive()', () => {
-        const directory = absoluteFrom('/a/b/c');
-        const fs = getFileSystem();
-        fs.ensureDir(directory);
-        const host = new NgtscCompilerHost(fs);
-        expect(host.useCaseSensitiveFileNames()).toEqual(fs.isCaseSensitive());
-      });
-    });
-
-    describe('getCanonicalFileName()', () => {
-      it('should return the original filename if FS is case-sensitive or lower case otherwise',
-         () => {
-           const directory = absoluteFrom('/a/b/c');
-           const fs = getFileSystem();
-           fs.ensureDir(directory);
-           const host = new NgtscCompilerHost(fs);
-           expect(host.getCanonicalFileName(('AbCd.ts')))
-               .toEqual(fs.isCaseSensitive() ? 'AbCd.ts' : 'abcd.ts');
-         });
-    });
   });
 });