fix(builtin): entry point from sources incorrectly used when binary is leveraged as tool, breaking resolution

[devversion]

Consider a nodejs_binary with a definition like the followed:

js_library(
  name = "lib",
  srcs = ["entrypoint.js", "constants.js"],
)

nodejs_binary(
  name = "bin",
  entry_point = "entrypoint.js",
  data = [":lib"],
)

This seems very standanrd and also works perfectly when the binary is invoked with bazel run. Via Bazel run, the Node Bash launcher resolves the entrypoint via the actual runfiles using rlocation.

If this binary is used as a tool, e.g. in npm_package_bin- then the entry point is resolved from the execroot, landing ultimately on the actual source file. This is wrong and breaks resolution in RBE (where only necessary sources are in the execroot).

This happens because the source entrypoint file. i.e. not the entrypoint.js from bazel-bin is also ending up being included in the runfiles of run_node via NodeRuntimeDepsInfo.

This mismatch breaks resolution, and also results in an incorrect/ unnecessary file being added to the action inputs. The entry point used in NodeRuntimeDepsInfo should be the one derived from the data sources of the rule, ensuring the entry-point can access its other files of the js_library.

i.e. entry-point should come from the data preferred, and if it's not found- then the source, or File can be directly used.

This fixes RBE for angular.io which started unveiling some issues
when we attempted to enable RBE via: angular/angular#48316