fix(builtin): linker no longer makes node_modules symlink to the root of the workspace output tree

BREAKING CHANGE:

Any nodejs_binary/nodejs_test processes with the linker enabled (--nobazel_patch_module_resolver is set) that were relying on standard node_module resolution to resolve manfest file paths such as `my_workspace/path/to/output/file.js` must now use the runfiles helper such as.

Previously:
```
const absPath = require.resolve('my_workspace/path/to/output/file.js');
```
With runfiles helper:
```
const runfiles = require(process.env['BAZEL_NODE_RUNFILES_HELPER']);
const absPath = runfiles.resolve('my_workspace/path/to/output/file.js');
```

Author: gregmagolan

internal/linker/link_node_modules.bzl

@@ -64,13 +64,7 @@ def write_node_modules_manifest(ctx, extra_data = []):
         extra_data: labels to search for npm packages that need to be linked (ctx.attr.deps and ctx.attr.data will always be searched)
     """
 
-    mappings = {
-        # We always map the workspace to itself to support absolute require like
-        # import from 'my_wksp/path/to/file' and it's always links to the bin_dir.
-        # If source files need to be required then they can be copied to the bin_dir
-        # with copy_to_bin.
-        ctx.workspace_name: ["execroot", ctx.bin_dir.path],
-    }
+    mappings = {}
     node_modules_root = ""
 
     # Look through data/deps attributes to find...