lsp-roslyn: fix arm64 detection and use default window/logMessage han… #5493

Job	Run time
test (ubuntu-latest, 27.2, false)	2m 9s
test (ubuntu-latest, 28.2, false)	2m 25s
test (ubuntu-latest, 29.4, false)	3m 21s
test (macos-latest, 28.2, false)	4m 25s
test (macos-latest, 29.4, false)	4m 26s
test (windows-latest, 27.2, false)	3m 55s
test (windows-latest, 28.2, false)	3m 25s
test (windows-latest, 29.4, false)	3m 55s
test (ubuntu-latest, snapshot, true)	1m 22s
test (macos-latest, snapshot, true)	2m 45s
test (windows-latest, snapshot, true)	5m 20s
	37m 28s

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