add env control for debug graph file's ump path

src/common/graph/utils/graph_utils.cc

@@ -60,6 +60,7 @@ const int32_t kBaseOfIntegerValue = 10;
 const char *const kDumpGeGraph = "DUMP_GE_GRAPH";
 const int kDumpGraphIndexWidth = 5;
 #endif
+const char *const kDumpGraphPath = "DUMP_GRAPH_PATH";
 const char *const kDumpGraphLevel = "DUMP_GRAPH_LEVEL";
 const char *const kDumpStrBuild = "Build";
 const char *const kDumpStrPartition = "partition";