[lldb][Windows] Enforce exec permission using Platform::Install() from Windows host (#91887)

Target::Install() set 0700 permissions for the main executable file.
Platform::Install() just copies permissions from the source. But the
permission eFilePermissionsUserExecute is missing on the Windows host. A
lot of tests failed in case of Windows host and Linux target because of
this issue. There is no API to provide the exec flag. This patch set the
permission eFilePermissionsUserExecute for all files installed via
Platform::Install() from the Windows host. It fixes a lot of tests in
case of Windows host and Linux target.