Move "android-cloexec-dup" into art_clang_tidy_errors

As part of the changes done in aosp/742964, an helper method called
DupCloexec was defined in libartbase/base/file_utils.{h, cc} specifically
to provide a single entry point for all places in need to call the
dup(2) system call, replacing it with fcntl with the F_DUPFD_CLOEXEC
flag whenever possible. Hence, it should be safe to ignore the warning
triggered by clang-tidy within the DupCloexec method, and set
"android-cloexec-dup" among the clang-tidy errors to prevent it
from happening again in the future.

Bug: 213953102
Test: m tidy-art
Change-Id: Ia16b805dc37d2d842feb0636f4cb459f989ac4bd
diff --git a/build/Android.bp b/build/Android.bp
index ccc30ef..382b0a3 100644
--- a/build/Android.bp
+++ b/build/Android.bp
@@ -28,6 +28,7 @@
 }
 
 art_clang_tidy_errors = [
+    "android-cloexec-dup",
     "android-cloexec-open",
     "bugprone-argument-comment",
     "bugprone-lambda-function-name",
@@ -46,12 +47,6 @@
     "performance-unnecessary-value-param",
 ]
 
-art_clang_tidy_allowed = [
-    // Many files have these warnings. Move them to art_clang_tidy_errors
-    // when all files are free of these warnings.
-    "android-cloexec-dup",
-]
-
 art_clang_tidy_disabled = [
     "-google-default-arguments",
     // We have local stores that are only used for debug checks.
@@ -249,7 +244,7 @@
         },
     },
 
-    tidy_checks: art_clang_tidy_errors + art_clang_tidy_allowed + art_clang_tidy_disabled,
+    tidy_checks: art_clang_tidy_errors + art_clang_tidy_disabled,
 
     tidy_checks_as_errors: art_clang_tidy_errors,
 
diff --git a/libartbase/base/file_utils.cc b/libartbase/base/file_utils.cc
index ed883f8..2396289 100644
--- a/libartbase/base/file_utils.cc
+++ b/libartbase/base/file_utils.cc
@@ -735,7 +735,7 @@
 #if defined(__linux__)
   return fcntl(fd, F_DUPFD_CLOEXEC, 0);
 #else
-  return dup(fd);
+  return dup(fd); // NOLINT
 #endif
 }