Correct failure of netty build component on s390x (due to zip -qd nee…

…ding something to delete)

Build on s390x fails because the process to remove unnecessary libraries from netty was not configured for x86.  As a result, zip -d failed because it had nothing to remove.  This PR does two things:

1.  Adds conditions for s390x to the src and third_party BUILD files, and
2.  Adds a condition to the genrule so that 'zip -d' does not execute if there's nothing to do.

See also Issue #9263; Pull Requests #9346 and #9945

Closes #10643.

PiperOrigin-RevId: 294698707

src/conditions/BUILD

@@ -16,6 +16,12 @@ config_setting(
     visibility = ["//visibility:public"],
 )
 
+config_setting(
+    name = "linux_s390x",
+    values = {"cpu": "s390x"},
+    visibility = ["//visibility:public"],
+)
+
 config_setting(
     name = "linux_x86_64",
     values = {"cpu": "k8"},