bug(linux): artifacts download is missing hextobin component

[mcdurdin]

e.g. https://build.palaso.org/buildConfiguration/KeymanLinux_TestPullRequests/603823?buildTab=artifacts keyman-19.0.193.tgz, extract and build:

marc@quamby-ubuntu:~/Downloads/keyman$ ./build.sh
[/home/marc/Downloads/keyman] Local build environment detected:  setting --debug
[/home/marc/Downloads/keyman] build.sh parameters: <--debug>
[/home/marc/Downloads/keyman] ## child build:common starting...
[common] child build, parameters: <--builder-child --deps build --debug>
[common] ## child build:resources starting...
[resources] child build, parameters: <--builder-child --deps build --debug>
[common] ## child build:resources completed successfully
[common] ## child build:linux starting...
[common/linux] child build, parameters: <--builder-child --deps build --debug>
[common] ## child build:linux completed successfully
[/home/marc/Downloads/keyman] ## child build:common completed successfully
[/home/marc/Downloads/keyman] ## child build:core starting...
[core] child build, parameters: <--builder-child --deps build --debug>
[core] Automatically running following required actions with missing outputs:
[core] * configure:wasm
[core] * configure:arch
[core] ## configure:wasm starting...
/home/marc/Downloads/keyman/resources/builder.inc.sh: line 2077: /home/marc/Downloads/keyman/common/tools/hextobin/build.sh: No such file or directory
[core] ## Dependency failed with exit code 127
[core] ## configure:wasm failed
[/home/marc/Downloads/keyman] ## child script '/home/marc/Downloads/keyman/core/build.sh build' failed with exit code 127