fix: Fix intermittent deadlock in grouped allocator (#42524)

issue: #42523
Resolve deadlock issue in GroupedAllocator where resource release
notifications fail to propagate across hierarchy levels, causing child
allocators to wait indefinitely.

Changes include:
- Add recursive notify() method to GroupedAllocator
- Ensure all child allocators receive resource release notifications
- Fix TOCTOU race condition in hierarchical resource management

This resolves the intermittent test timeout in TestGroupedAllocator test
that exhibited deadlock due to missed condition notifications.

Signed-off-by: Wei Liu <wei.liu@zilliz.com>

pkg/util/vralloc/sharedalloc.go

@@ -110,6 +110,14 @@ func (ga *GroupedAllocator) GetAllocator(name string) Allocator[string] {
 	return ga.children[name]
 }
 
+// Note: GroupedAllocator should notify its all children.
+func (ga *GroupedAllocator) notify() {
+	ga.SharedAllocator.notify()
+	for _, child := range ga.children {
+		child.notify()
+	}
+}
+
 type GroupedAllocatorBuilder struct {
 	ga GroupedAllocator
 }