Bazel: Replace PACKAGE_NAME constant with package_name() function

PACKAGE_NAME was deprecated in favor of package_name() function and is
going to be removed in future Bazel releases. Moreover Bazel is trying
to set --incompatible_package_name_is_a_function=true per default to
enforce Bazel users to stop using it: [1].

[1] bazelbuild/bazel#5827

Change-Id: I4d1a6ccbeae611fdd0e9c1e9fdd89b6dd1294f36

tools/bzl/js.bzl

@@ -426,4 +426,4 @@ _vulcanize_rule = rule(
 
 def vulcanize(*args, **kwargs):
     """Vulcanize runs vulcanize and crisper on a set of sources."""
-    _vulcanize_rule(*args, pkg = PACKAGE_NAME, **kwargs)
+    _vulcanize_rule(*args, pkg = native.package_name(), **kwargs)

tools/bzl/license.bzl

@@ -39,7 +39,7 @@ def license_test(name, target):
     if target[0] not in ":/":
         target = ":" + target
     if target[0] != "/":
-        target = "//" + PACKAGE_NAME + target
+        target = "//" + native.package_name() + target
 
     forbidden = "//lib:LICENSE-DO_NOT_DISTRIBUTE"
     native.genquery(