android: Update shader toolchain revisions

Pulled from:
https://github.com/google/shaderc/blob/90a90d6f745704ac05afe70b7e8f759bec2ff493/known_good.json
diff --git a/build-android/shaderc_revision_android b/build-android/shaderc_revision_android
index c429814..bf6696c 100644
--- a/build-android/shaderc_revision_android
+++ b/build-android/shaderc_revision_android
@@ -1 +1 @@
-aa8f3767f01aae4cfe0cb3b142753a1ee7434091
+12fb656ab20ea9aa06e7084a74e5ff832b7ce2da