toolchain: Switch back to tracked revisions on Android

This allows us to recreate the entire LVL package from any point in history.
We continue to pull known good revisions from AOSP.
diff --git a/build-android/spirv-tools_revision_android b/build-android/spirv-tools_revision_android
index 1f7391f..0fedfe9 100644
--- a/build-android/spirv-tools_revision_android
+++ b/build-android/spirv-tools_revision_android
@@ -1 +1 @@
-master
+1401a61b1e7d1516578171a94edbac33858fb1a2