revert rewind of isl submodule

Sven Verdoolaege · Sven Verdoolaege · commit 7fafcc13e0ea · 2018-07-25T11:46:11.000+02:00
For some reason, dcf4d83 (Use NO_CUDA_SDK rather than undefine CUDA_HOME, Thu Jul 12 14:55:39 2018 -0700) rewinds the isl submodule, breaking compilation (when building with WITH_BINDINGS). Revert to the original state.
diff --git a/third-party/islpp b/third-party/islpp
@@ -1 +1 @@
-Subproject commit f8cf7cf1b0ca606d8adb0b88d60200c4a858d36c
+Subproject commit adefea12a80d7c1846342227d85133a10b20261e
