perf: remove unnecessary calls to 'to_list' (#737)

lib/private/copy_directory_toolchain.bzl

@@ -57,7 +57,7 @@ CopyToDirectoryInfo = provider(
 )
 
 def _copy_directory_toolchain_impl(ctx):
-    binary = ctx.attr.bin.files.to_list()[0]
+    binary = ctx.file.bin
 
     default_info = DefaultInfo(
         files = depset([binary]),

lib/private/copy_to_directory_toolchain.bzl

@@ -57,7 +57,7 @@ CopyToDirectoryInfo = provider(
 )
 
 def _copy_to_directory_toolchain_impl(ctx):
-    binary = ctx.attr.bin.files.to_list()[0]
+    binary = ctx.file.bin
 
     default_info = DefaultInfo(
         files = depset([binary]),

lib/private/jq_toolchain.bzl

@@ -65,7 +65,7 @@ JqInfo = provider(
 )
 
 def _jq_toolchain_impl(ctx):
-    binary = ctx.attr.bin.files.to_list()[0]
+    binary = ctx.file.bin
 
     # Make the $(JQ_BIN) variable available in places like genrules.
     # See https://docs.bazel.build/versions/main/be/make-variables.html#custom_variables

lib/private/yq_toolchain.bzl

@@ -314,7 +314,7 @@ YqInfo = provider(
 )
 
 def _yq_toolchain_impl(ctx):
-    binary = ctx.attr.bin.files.to_list()[0]
+    binary = ctx.file.bin
 
     # Make the $(YQ_BIN) variable available in places like genrules.
     # See https://docs.bazel.build/versions/main/be/make-variables.html#custom_variables