windows path tweaks & debug duped path #1139

Job	Run time
initialise	5s
quick-check	5m 26s
macos-bootstrap-chez	7m 15s
nix-bootstrap-chez	18m 56s
ubuntu-bootstrap-racket	14m 6s
ubuntu-bootstrap-chez	6m 39s
ubuntu-self-host-previous-version	9m 58s
windows-bootstrap-chez	24m 2s
ubuntu-self-host-chez	9m 57s
ubuntu-build-api	4m 14s
macos-self-host-chez	14m 57s
ub-pack-test-pack	0s
ub-test-elab-util	0s
ub-test-frex	0s
ub-test-collie	0s
ub-pack-test-lsp	0s
ub-test-katla-and-html	0s
ubuntu-self-host-racket	0s
windows-self-host-racket	0s
	1h 55m 35s

Provide feedback