COFF: Do not ignore /merge if /debug is specified.

Previously, we ignore /merge option if /debug is specified
because I thought that was MSVC linker did. This was wrong.
/merge shouldn't be ignored even in debug mode.

llvm-svn: 243375

lld/COFF/Writer.cpp

@@ -168,8 +168,6 @@ void Writer::dedupCOMDATs() {
 
 static StringRef getOutputSection(StringRef Name) {
   StringRef S = Name.split('$').first;
-  if (Config->Debug)
-    return S;
   auto It = Config->Merge.find(S);
   if (It == Config->Merge.end())
     return S;

lld/test/COFF/merge.test

@@ -1,6 +1,6 @@
 # RUN: yaml2obj < %s > %t.obj
 # RUN: lld -flavor link2 /out:%t.exe /entry:main /subsystem:console /force \
-# RUN:   /merge:.foo=.abc /merge:.bar=.def %t.obj
+# RUN:   /merge:.foo=.abc /merge:.bar=.def %t.obj /debug
 # RUN: llvm-readobj -sections %t.exe | FileCheck %s
 
 # CHECK: Name: .def