Fixes formatting of empty blocks.

We now only put empty blocks into a single line, if all of:
- all tokens of the structural element fit into a single line
- we're not in a control flow statement

Note that we usually don't put record definitions into a single line, as
there's usually at least one more token (the semicolon) after the
closing brace. This doesn't hold when we are in a context where there is
no semicolon, like "enum E {}".

There were some missing tests around joining lines around the corner
cases of the allowed number of columns, so this patch adds some.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@173055 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Index/comment-to-html-xml-conversion.cpp b/test/Index/comment-to-html-xml-conversion.cpp
index c1ec08e..0577eb0 100644
--- a/test/Index/comment-to-html-xml-conversion.cpp
+++ b/test/Index/comment-to-html-xml-conversion.cpp
@@ -713,7 +713,7 @@
 
 /// Aaa.
 enum comment_to_xml_conversion_15 {
-// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: EnumDecl=comment_to_xml_conversion_15:{{.*}} FullCommentAsXML=[<Enum file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_15</Name><USR>c:@E@comment_to_xml_conversion_15</USR><Declaration>enum comment_to_xml_conversion_15{{( : int)?}} {\n}</Declaration><Abstract><Para> Aaa.</Para></Abstract></Enum>]
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:6: EnumDecl=comment_to_xml_conversion_15:{{.*}} FullCommentAsXML=[<Enum file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="6"><Name>comment_to_xml_conversion_15</Name><USR>c:@E@comment_to_xml_conversion_15</USR><Declaration>enum comment_to_xml_conversion_15{{( : int)?}} {}</Declaration><Abstract><Para> Aaa.</Para></Abstract></Enum>]
 
   /// Aaa.
   comment_to_xml_conversion_16
@@ -722,7 +722,7 @@
 
 /// Aaa.
 enum class comment_to_xml_conversion_17 {
-// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:12: EnumDecl=comment_to_xml_conversion_17:{{.*}} FullCommentAsXML=[<Enum file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="12"><Name>comment_to_xml_conversion_17</Name><USR>c:@E@comment_to_xml_conversion_17</USR><Declaration>enum class comment_to_xml_conversion_17 : int {\n}</Declaration><Abstract><Para> Aaa.</Para></Abstract></Enum>]
+// CHECK: comment-to-html-xml-conversion.cpp:[[@LINE-1]]:12: EnumDecl=comment_to_xml_conversion_17:{{.*}} FullCommentAsXML=[<Enum file="{{[^"]+}}comment-to-html-xml-conversion.cpp" line="[[@LINE-1]]" column="12"><Name>comment_to_xml_conversion_17</Name><USR>c:@E@comment_to_xml_conversion_17</USR><Declaration>enum class comment_to_xml_conversion_17 : int {}</Declaration><Abstract><Para> Aaa.</Para></Abstract></Enum>]
 
   /// Aaa.
   comment_to_xml_conversion_18