Add BUILD_BROKEN_PLUGIN_VALIDATION flag

Use is to specify the list of plugins are are not allowed.

Ignore-AOSP-First: Requires an internal only change to not break when submitted
Test: CI
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:f24be9dba9b53b0c1682929253a3eba9af7a4c31)
Merged-In: Ia2fe83d82ead618e480e99a82b1b825ed08d3eab
Change-Id: Ia2fe83d82ead618e480e99a82b1b825ed08d3eab
diff --git a/core/board_config.mk b/core/board_config.mk
index bdfb279..c8ec5a9 100644
--- a/core/board_config.mk
+++ b/core/board_config.mk
@@ -174,6 +174,7 @@
 
 
 _build_broken_var_list := \
+  BUILD_BROKEN_PLUGIN_VALIDATION \
   BUILD_BROKEN_CLANG_PROPERTY \
   BUILD_BROKEN_CLANG_ASFLAGS \
   BUILD_BROKEN_CLANG_CFLAGS \