Fix declaration emit when the packages are included through symlinks

[sheetalkamat]

• Earlier when looking at the redirects, we didnt use Path which is the key so in cases of symlink having different cases, we were not including the redirects resulting in the errors during decl emit
  Fixes Type resolution in linked packages - Updated Repro #36866
• Converted symlink tests to virtualFileSystemWithWatch since mounting fs used in tscwatch baseline scenarios did not preserve symlinks correctly.
• So when doing that realised that one of the test case where package is included as a dependency of package included, we werent reporting error as expected. (It worked earlier because symlink realpath always came out to be same as actual path instead of translating to actual path during mounting of fs scenarios) To fix this, exclude paths that dont have node_modules if any of the paths for the given module is through node_modules
• Refactored ModuleSpecifierResolutionHost which shouldn't have been in Public API