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

rsApiContext.cpp

diff --git a/rsApiContext.cpp b/rsApiContext.cpp
index 8cb2993..3f350cd 100644
--- a/rsApiContext.cpp
+++ b/rsApiContext.cpp
@@ -21,8 +21,9 @@
 #include "rsgApiFuncDecl.h"
 #include "rsFifo.h"
 
-using namespace android;
-using namespace android::renderscript;
+using android::renderscript::Context;
+using android::renderscript::Device;
+using android::renderscript::ObjectBase;
 
 /*
  * This global will be found by the debugger and will have its value flipped.