Fix google-build-using-namespace warnings in rs.

* Most files define classes in renderscript namespace.
  Define them in the namespace instead of "using namespace ...".
  Some files define global C++ names, and we replace
  "using namespace ..." with using declarations of the required names.
* Add "NOLINT" comment to rsg_generator.c output code to suppress
  such warnings.

Bug: 32670901
Test: build with WITH_TIDY=1
Change-Id: I9b0edcad3e1fb37c79927b05fd58fb1a301bdf22

rsThreadIO.cpp

diff --git a/rsThreadIO.cpp b/rsThreadIO.cpp
index 5001d7a..ceec54a 100644
--- a/rsThreadIO.cpp
+++ b/rsThreadIO.cpp
@@ -26,8 +26,8 @@
 #include <poll.h>
 
 
-using namespace android;
-using namespace android::renderscript;
+namespace android {
+namespace renderscript {
 
 ThreadIO::ThreadIO() {
     mRunning = true;
@@ -215,3 +215,5 @@
     return true;
 }
 
+} // namespace renderscript
+} // namespace android