mac: Convert GN libs lists to frameworks in //rlz.

GN recently added support for Apple frameworks to link, rather than
overloading the libs lists. This pulls .frameworks out of the libs
lists, so that GN can stop supporting .frameworks in libs in the
future.

Bug: 1052560
Change-Id: I5c47b3c44a7030a8373bee73dbf7551bd88f4c9c
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2276657
Commit-Queue: Robert Sesek <rsesek@chromium.org>
Commit-Queue: Nico Weber <thakis@chromium.org>
Reviewed-by: Nico Weber <thakis@chromium.org>
Cr-Commit-Position: refs/heads/master@{#784210}

rlz/BUILD.gn

@@ -85,7 +85,7 @@ if (!is_android) {
     }
 
     if (is_mac) {
-      libs = [
+      frameworks = [
         "Foundation.framework",
         "IOKit.framework",
       ]