Fix known typos

Sweep the codebase for common typos. Includes some changes to visible function
names that were misspelt.

llvm-svn: 200018
diff --git a/llvm/lib/CodeGen/MachineScheduler.cpp b/llvm/lib/CodeGen/MachineScheduler.cpp
index 2de3d20..beb7243 100644
--- a/llvm/lib/CodeGen/MachineScheduler.cpp
+++ b/llvm/lib/CodeGen/MachineScheduler.cpp
@@ -1976,7 +1976,7 @@
   }
   else {
     // After updating ZoneCritResIdx and ExpectedLatency, check if we're
-    // resource limited. If a stall occured, bumpCycle does this.
+    // resource limited. If a stall occurred, bumpCycle does this.
     unsigned LFactor = SchedModel->getLatencyFactor();
     IsResourceLimited =
       (int)(getCriticalCount() - (getScheduledLatency() * LFactor))