[gn build] Port 2aff3c6

Author: llvmgnsyncbot

llvm/utils/gn/secondary/llvm/lib/CAS/BUILD.gn

@@ -9,6 +9,7 @@ static_library("CAS") {
     "MappedFileRegionArena.cpp",
     "ObjectStore.cpp",
     "OnDiskCommon.cpp",
+    "OnDiskDataAllocator.cpp",
     "OnDiskTrieRawHashMap.cpp",
   ]
 }

llvm/utils/gn/secondary/llvm/unittests/CAS/BUILD.gn

@@ -10,6 +10,7 @@ unittest("CASTests") {
     "ActionCacheTest.cpp",
     "CASTestConfig.cpp",
     "ObjectStoreTest.cpp",
+    "OnDiskDataAllocatorTest.cpp",
     "OnDiskTrieRawHashMapTest.cpp",
     "ProgramTest.cpp",
   ]