[automerger skipped] Merge "[DO NOT MERGE] Set RBE_DIR default value to point...

[automerger skipped] Merge "[DO NOT MERGE] Set RBE_DIR default value to point to prebuilts in tree." into qt-dev am: d9cf148d am: 4f66e757 -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/build/+/12593960

Change-Id: I75567bd0c2896aa053fd7982d3f278b2a0f9b9b9