Move platform constraints to bazel_common_rules.

This enables sharing of platform constraints between platform and kernel builds.

Bug: 304594734

Test: treehugger
Change-Id: I48091eeaf2e529c3f180ba056da3935911868b14
diff --git a/bp2build/cc_prebuilt_library_shared_test.go b/bp2build/cc_prebuilt_library_shared_test.go
index 58c0a70..1a9579a 100644
--- a/bp2build/cc_prebuilt_library_shared_test.go
+++ b/bp2build/cc_prebuilt_library_shared_test.go
@@ -52,8 +52,8 @@
 			ExpectedBazelTargets: []string{
 				MakeBazelTarget("cc_prebuilt_library_shared", "libtest", AttrNameToString{
 					"shared_library": `select({
-        "//build/bazel/platforms/arch:arm": "libg.so",
-        "//build/bazel/platforms/arch:arm64": "libf.so",
+        "//build/bazel_common_rules/platforms/arch:arm": "libg.so",
+        "//build/bazel_common_rules/platforms/arch:arm64": "libf.so",
         "//conditions:default": None,
     })`,
 				}),