When maximum space size flags are set, overwrite the resource constraints.

src/heap.cc

Index: src/heap.cc
diff --git a/src/heap.cc b/src/heap.cc
index ca7cea5ac17ec8ae2f3a109ca29e05423a1edb3c..c764b31b395efdb95cf861a652bf9dbabf0a21c5 100644
--- a/src/heap.cc
+++ b/src/heap.cc
@@ -5014,6 +5014,17 @@ bool Heap::ConfigureHeap(int max_semispace_size,
                          intptr_t code_range_size) {
   if (HasBeenSetUp()) return false;
 
+  // If max space size flags are specified overwrite the configuration.
+  if (FLAG_max_new_space_size > 0) {
+    max_semispace_size = FLAG_max_new_space_size * kLumpOfMemory;
+  }
+  if (FLAG_max_old_space_size > 0) {
+    max_old_gen_size = FLAG_max_old_space_size * kLumpOfMemory;
+  }
+  if (FLAG_max_executable_size > 0) {
+    max_executable_size = FLAG_max_executable_size * kLumpOfMemory;
+  }
+
   if (FLAG_stress_compaction) {
     // This will cause more frequent GCs when stressing.
     max_semispace_size_ = Page::kPageSize;