[test] Import Glibc for Android as well

Expand operating system check to import Glibc on all non-Darwin
platforms, including Android.

Author: modocache

test/1_stdlib/tgmath_optimized.swift

@@ -3,7 +3,7 @@
 // RUN: %target-run %t/a.out
 // REQUIRES: executable_test
 
-#if os(Linux) || os(FreeBSD)
+#if os(Linux) || os(FreeBSD) || os(Android)
   import Glibc
 #else
   import Darwin