Generating new artifact called emulator-info.txt

For a given build of sys-image, a stable emulator build is added to the
emulator-info.txt which will end up in generated emulator-info.txt artifact.
This information will be used by the testing infrastructure while using
GCE instances.

Bug: b/110053895

Test: A local build will generate "emulator-info.txt" with the following
"require version-emulator=" line.


Change-Id: Ib0807d7da3d49bc8635515b369c231fc2c6d5d9a
diff --git a/emulator-info.txt b/emulator-info.txt
index 0d6e6cf..1d64e25 100644
--- a/emulator-info.txt
+++ b/emulator-info.txt
@@ -1,2 +1,2 @@
 # Emulator (stable) version
-require version-emulator=4898683
+require version-emulator=5441143