[IR] Refactor attribute methods in Function class (NFC)

Rename the functions that query the optimization kind attributes.

Differential revision: https://reviews.llvm.org/D60287

llvm-svn: 357731
diff --git a/llvm/lib/Analysis/RegionPass.cpp b/llvm/lib/Analysis/RegionPass.cpp
index ea117ea..6c0d17b 100644
--- a/llvm/lib/Analysis/RegionPass.cpp
+++ b/llvm/lib/Analysis/RegionPass.cpp
@@ -288,7 +288,7 @@
   if (Gate.isEnabled() && !Gate.shouldRunPass(this, getDescription(R)))
     return true;
 
-  if (F.optForNone()) {
+  if (F.hasOptNone()) {
     // Report this only once per function.
     if (R.getEntry() == &F.getEntryBlock())
       LLVM_DEBUG(dbgs() << "Skipping pass '" << getPassName()