Pass directory path from call-site

[am11]

When init-compiler is sourced (as opposed to eval'd), the script was giving a non-fatal error, e.g. on mono x64: pipeline-logging-functions.sh: No such file or directory. We use Azure logging functions in error cases, so it went unnoticed.

This PR uses the same simple mechanism for sourced scripts we have used in other places; pass the directory path from all call-sites as an argument. Also quoted the positional arguments.

[dotnet-issue-labeler]

I couldn't figure out the best area label to add to this PR. If you have write-permissions please help me learn by adding exactly one area label.

[am11]

cc @jkoritzinsky, @janvorli, noticed this when I was looking at mono logs for another issue: https://dev.azure.com/dnceng/public/_build/results?buildId=1397492&view=logs&j=38c63b74-c97f-5bda-376d-1084248ecb57&t=b7130259-7da2-5518-9023-82792e689970&l=98

In gen-buildsys.sh, it doesn't warn because we are at the same relative distance.

[am11]

Before:

Running 'bash -c 'source /__w/1/s/eng/common/native/init-compiler.sh x64 clang && ....

/__w/1/s/eng/common/native/init-compiler.sh: line 16: /__w/1/s/artifacts/obj/mono/Linux.x64.Debug/../pipeline-logging-functions.sh: No such file or directory

(the build still continues and succeeds because it's not running with set -e)

After:

Running 'bash -c 'source /__w/1/s/eng/common/native/init-compiler.sh "/__w/1/s/eng/common/native" "x64" "clang" && ....

It regressed in #59018.

[janvorli]

LGTM, thank you!

[am11]

win x64 failure is unrelated to PR changes: #29683.