FASTBuild: optimize generated file size

Two optimizations here:
1. Remove non-mandatory aliases (I only used them for debugging).
2. Make objects lists' name shorter

Both of those improvements contribute to the decrease of the FASTBuild DB file, since they are getting serialized.

Source/cmFastbuildNormalTargetGenerator.cxx

@@ -1307,8 +1307,7 @@ cmFastbuildNormalTargetGenerator::GenerateObjects()
                                 objectListNode);
       ComputePCH(*source, objectListNode, createdPCH);
 
-      objectListNode.Name =
-        cmStrCat(language, "_ObjectGroup_", GetTargetName());
+      objectListNode.Name = cmStrCat(this->GetName(), '_', language, "_Objs");
       // TODO: Ask cmake the output objects and group by extension instead
       // of doing this
       if (language == "RC") {
@@ -1325,13 +1324,12 @@ cmFastbuildNormalTargetGenerator::GenerateObjects()
     }
   }
 
-  int groupNameCount = 1;
+  int groupNameCount = 0;
 
   for (auto& val : nodesPermutations) {
     auto& objectListNode = val.second;
     objectListNode.Name =
-      cmStrCat(objectListNode.Name, "-", objectListNode.CompilerOutputPath,
-               "-", std::to_string(groupNameCount++));
+      cmStrCat(objectListNode.Name, "_", std::to_string(++groupNameCount));
     LogMessage(cmStrCat("ObjectList name: ", objectListNode.Name));
   }
 

Source/cmGlobalFastbuildGenerator.cxx

@@ -1078,8 +1078,13 @@ void cmGlobalFastbuildGenerator::WriteExec(FastbuildExecNode const& Exec,
   }
   Indent(indent);
   *BuildFileStream << "}\n";
-  WriteAlias(Exec.OutputsAlias);
-  WriteAlias(Exec.ByproductsAlias);
+  static bool const verbose = GlobalSettingIsOn(FASTBUILD_VERBOSE_GENERATOR) ||
+    cmSystemTools::HasEnv(FASTBUILD_VERBOSE_GENERATOR);
+  // Those aliases are only used for troubleshooting the generated file.
+  if (verbose) {
+    WriteAlias(Exec.OutputsAlias);
+    WriteAlias(Exec.ByproductsAlias);
+  }
 }
 
 void cmGlobalFastbuildGenerator::WriteObjectList(