[clangd] Split code-completion tests out of ClangdTests. NFC.

Summary:
Common parts are mostly FS related, so pulled out TestFS.h for the common stuff.
Deliberately resisted cleaning up much here, so this is pretty mechanical.

Reviewers: hokein

Subscribers: klimek, mgorny, ilya-biryukov, cfe-commits

Differential Revision: https://reviews.llvm.org/D40784

llvm-svn: 319741
diff --git a/clang-tools-extra/clangd/CodeComplete.cpp b/clang-tools-extra/clangd/CodeComplete.cpp
index 04c2795..a8203b5 100644
--- a/clang-tools-extra/clangd/CodeComplete.cpp
+++ b/clang-tools-extra/clangd/CodeComplete.cpp
@@ -163,7 +163,6 @@
   return Result;
 }
 
-
 /// A scored code completion result.
 /// It may be promoted to a CompletionItem if it's among the top-ranked results.
 struct CompletionCandidate {
@@ -349,9 +348,8 @@
     : public CompletionItemsCollector {
 
 public:
-  PlainTextCompletionItemsCollector(
-      const CodeCompleteOptions &CodeCompleteOpts,
-      CompletionList &Items)
+  PlainTextCompletionItemsCollector(const CodeCompleteOptions &CodeCompleteOpts,
+                                    CompletionList &Items)
       : CompletionItemsCollector(CodeCompleteOpts, Items) {}
 
 private:
@@ -386,9 +384,8 @@
 class SnippetCompletionItemsCollector final : public CompletionItemsCollector {
 
 public:
-  SnippetCompletionItemsCollector(
-      const CodeCompleteOptions &CodeCompleteOpts,
-      CompletionList &Items)
+  SnippetCompletionItemsCollector(const CodeCompleteOptions &CodeCompleteOpts,
+                                  CompletionList &Items)
       : CompletionItemsCollector(CodeCompleteOpts, Items) {}
 
 private: