Rename bzl files to scl

These files don't have anything to do with bazel, they just use starlark as a configuration
language. Bazel recently introduced the scl file extension to use for this format, which doesn't
have any bazel-specific symbols. Use that extension for our pure starlark files as well.

Bug: 309686282
Test: Presubmits
Change-Id: I7b08f342e7fb94405a52af0918ae6a7d542f3282
diff --git a/core/release_config.bzl b/core/release_config.bzl
new file mode 120000
index 0000000..ffb70a3
--- /dev/null
+++ b/core/release_config.bzl
@@ -0,0 +1 @@
+release_config.scl
\ No newline at end of file
diff --git a/core/release_config.mk b/core/release_config.mk
index 5993e85..e1e0726 100644
--- a/core/release_config.mk
+++ b/core/release_config.mk
@@ -82,16 +82,6 @@
 )
 FLAG_DECLARATION_FILES :=
 
-# Make sure that the flag definitions are included for vendor/google builds.
-# This decouples the change in vendor/google/release/release_config_map.mk
-# from this logic change.
-# TODO: Remove this once the vendor/google FLAG_DECLARATION_FILES change is there.
-$(if $(wildcard vendor/google/release/release_config_map.mk),\
-  $(if $(filter vendor/google/release/build_flags.bzl,$(_flag_declaration_files)),,\
-    $(eval _flag_declaration_files := vendor/google/release/build_flags.bzl $(_flag_declaration_files)) \
-  ) \
-)
-
 # If TARGET_RELEASE is set, fail if there is no matching release config
 # If it isn't set, no release config files will be included and all flags
 # will get their default values.
diff --git a/core/release_config.bzl b/core/release_config.scl
similarity index 98%
rename from core/release_config.bzl
rename to core/release_config.scl
index a29f3f2..101f119 100644
--- a/core/release_config.bzl
+++ b/core/release_config.scl
@@ -15,7 +15,7 @@
 Export build flags (with values) to make.
 """
 
-load("//build/bazel/utils:schema_validation.bzl", "validate")
+load("//build/bazel/utils:schema_validation.scl", "validate")
 
 # Partitions that get build system flag summaries
 _flag_partitions = [