The current roll_aosp.sh is generating an invalid Android.bp by
including the local repo's .git file:

cc_genrule {
    name: "angle_commit_id",
    tool_files: [
        "src/commit_id.py",
    ],
    cmd: "$(location) gen $(location commit.h)",
    srcs: [
        ".git/refs/heads/rollAngle",
    ],
    sdk_version: "28",
    out: [
        "commit.h",
    ],
}

This is fixed by enabling the GN arg 'angle_enable_commit_id=false' in
the script:

cc_genrule {
    name: "angle_commit_id",
    tool_files: [
        "src/commit_id.py",
    ],
    cmd: "$(location) gen $(location commit.h)",
    sdk_version: "28",
    out: [
        "commit.h",
    ],
}

Bug: angleproject:5050
Test: Manual verification in AOSP checkout
Change-Id: I08a08084c4c25411b29b22544c2ed8c06f6f54d8
Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2412790Reviewed-by: Geoff Lang <geofflang@chromium.org>