Revert "Rename ANDROID_PRODUCT_OUT -> PRODUCT_OUT."

Using ANDROID_PRODUCT_OUT is actually the right thing to do.

The reason the bots failed was because I've changed their export to PRODUCT_OUT. I've reverted that change here:
https://chromium-review.googlesource.com/c/chromium/tools/build/+/847512

This reverts commit bf7fbc28a885d50a336eb7a191d24dc15f075360.

Change-Id: Ic67586bc33b8921dd20946238b59fe522fe784dd
1 file changed