[gn build] (manually) port ded733bd4 (llvm-remark-size-diff)

llvm/utils/gn/secondary/llvm/test/BUILD.gn

@@ -281,6 +281,7 @@ group("test") {
     "//llvm/tools/llvm-rc:symlinks",
     "//llvm/tools/llvm-readobj:symlinks",
     "//llvm/tools/llvm-reduce",
+    "//llvm/tools/llvm-remark-size-diff",
     "//llvm/tools/llvm-rtdyld",
     "//llvm/tools/llvm-sim",
     "//llvm/tools/llvm-size",

llvm/utils/gn/secondary/llvm/tools/llvm-remark-size-diff/BUILD.gn

@@ -0,0 +1,10 @@
+executable("llvm-remark-size-diff") {
+  deps = [
+    "//llvm/lib/Demangle",
+    "//llvm/lib/IR",
+    "//llvm/lib/Object",
+    "//llvm/lib/Remarks",
+    "//llvm/lib/Support",
+  ]
+  sources = [ "RemarkSizeDiff.cpp" ]
+}