stage2/lw: Fix absolute path detection on Windows #123

Job	Run time
build	1m 48s
prepare_integration_test_matrix	4s
integration_tests (fabric, gg.essential.loader.stage1.Stage1Tests)	1m 0s
integration_tests (launchwrapper, gg.essential.loader.stage1.Stage1DevEnvTests)	1m 0s
integration_tests (launchwrapper, gg.essential.loader.stage0.Stage0Tests)	1m 6s
integration_tests (launchwrapper, gg.essential.loader.stage2.Stage2FailureTests)	3m 12s
integration_tests (launchwrapper, gg.essential.loader.stage2.Stage2Tests)	2m 6s
integration_tests (fabric, gg.essential.loader.JiJTests)	1m 4s
integration_tests (launchwrapper, gg.essential.loader.stage2.Stage2BundledTests)	3m 11s
integration_tests (launchwrapper, gg.essential.loader.stage1.Stage1TweakerTests)	1m 1s
integration_tests (launchwrapper, gg.essential.loader.stage2.Stage2MixinTests)	1m 26s
integration_tests (fabric, gg.essential.loader.IntegrationTests)	1m 3s
integration_tests (fabric, gg.essential.loader.stage1.Stage1BundledTests)	1m 8s
integration_tests (launchwrapper, gg.essential.loader.IntegrationTests)	1m 39s
integration_tests (fabric, gg.essential.loader.stage1.Stage1FailureTests)	1m 4s
integration_tests (launchwrapper, gg.essential.loader.stage2.RelaunchTests)	1m 22s
integration_tests (launchwrapper, gg.essential.loader.stage2.Stage0TweakClassDetectionTests)	1m 15s
test_report	22s
	24m 51s

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