Handle ARM "ret void" and function alignment with proper padding.

src/assembler_ia32.h

Index: src/assembler_ia32.h
diff --git a/src/assembler_ia32.h b/src/assembler_ia32.h
index 4cb6ee78239ac82899dd9163659602b2354d573b..f5675167be4d29da48580f1dbb4450aeb35b139b 100644
--- a/src/assembler_ia32.h
+++ b/src/assembler_ia32.h
@@ -352,6 +352,8 @@ public:
 
   SizeT getBundleAlignLog2Bytes() const override { return 5; }
 
+  const char *getNonExecPadDirective() const override { return ".p2align"; }
+
   llvm::ArrayRef<uint8_t> getNonExecBundlePadding() const override {
     static const uint8_t Padding[] = {0xF4};
     return llvm::ArrayRef<uint8_t>(Padding, 1);