fix warnings on Mac in tests

Fix these class of warnings:
- unused functions
- unused locals
- sign mismatch
- missing function prototypes
- missing newline at end of file
- 64 to 32 bit truncation

The changes prefer to link in dead code in the debug build
with 'if (false)' than to comment it out, but trivial cases
are commented out or sometimes deleted if it appears to be
a copy/paste error.
Review URL: https://codereview.appspot.com/6301045

git-svn-id: http://skia.googlecode.com/svn/trunk@4175 2bbb7eff-a529-9590-31e7-b0007b416f81
diff --git a/tests/ReadWriteAlphaTest.cpp b/tests/ReadWriteAlphaTest.cpp
index 4b3f671..536d0c5 100644
--- a/tests/ReadWriteAlphaTest.cpp
+++ b/tests/ReadWriteAlphaTest.cpp
@@ -12,7 +12,7 @@
 static const int X_SIZE = 12;
 static const int Y_SIZE = 12;
 
-void ReadWriteAlphaTest(skiatest::Reporter* reporter, GrContext* context) {
+static void ReadWriteAlphaTest(skiatest::Reporter* reporter, GrContext* context) {
 
 #if SK_SCALAR_IS_FIXED
     // GPU device known not to work in the fixed pt build.