[NFC] Pre- increment and decrement where possible

Author: AnthonyLatsis

include/swift/Remote/Failure.h

@@ -255,7 +255,7 @@ class Failure {
       result.append(text, next - text);
 
       // Skip the '%'.
-      next++;
+      ++next;
 
       // Do something based on the character after '%'.
       char c = *next++;

include/swift/Runtime/Concurrent.h

@@ -434,7 +434,7 @@ template <class ElemTy> struct ConcurrentReadableArray {
     }
 
     void deallocate() {
-      for (size_t i = 0; i < Count; i++) {
+      for (size_t i = 0; i < Count; ++i) {
         data()[i].~ElemTy();
       }
       free(this);