ICU-12515 first() should just call delegate

there won't be a suppressed break at position 0. first() should just call
into the delegate.

X-SVN-Rev: 39237

icu4c/source/common/filteredbrk.cpp

@@ -403,7 +403,8 @@ SimpleFilteredSentenceBreakIterator::next() {
 
 int32_t
 SimpleFilteredSentenceBreakIterator::first(void) {
-  return internalNext(fDelegate->first());
+  // Don't suppress a break opportunity at the beginning of text.
+  return fDelegate->first();
 }
 
 int32_t