[lldb/test] Disable TestStringLiteralExpr.test on Windows

This test, introduced by b042d15d, fails on
https://lab.llvm.org/buildbot/#/builders/83/builds/20933/steps/7/logs/stdio

but succeeds on other targets, see for instance
https://lab.llvm.org/buildbot/#/builders/68/builds/35462/steps/6/logs/stdio

This test is not be arch specific, just disabling it on Windows.