Move Android ucontext.h out of third_party.

Google is re-licensing this code under the standard dual license of
compiler-rt.

llvm-svn: 204128
GitOrigin-RevId: 0b5b3295e521e266ded60099c1e067120cd2ffaa
diff --git a/LICENSE.TXT b/LICENSE.TXT
index 596f874..aee8347 100644
--- a/LICENSE.TXT
+++ b/LICENSE.TXT
@@ -89,9 +89,3 @@
 University of Illinois to endorse or promote products derived from this
 Software.
 
-The following pieces of software have additional or alternate copyrights,
-licenses, and/or restrictions:
-
-Program             Directory
--------             ---------
-android headers     third_party/android