Wrong scope descriptions in puffin viewer when running profiled program multiple times

**Describe the bug**
The scope ids may change between different runs of the same program depending on the order the scopes are encountered as the program runs. This results in misleading information in the viewer.

**To Reproduce**
Steps to reproduce the behavior:
1. Start puffin viewer
2. Run program with random ordering of scopes
3. Close the program but not the puffin viewer
4. Run the same program again
5. See that the scope descriptions are wrong

**Expected behavior**
The scope descriptions should be correct even when running the program multiple times without restarting the viewer.

**Screenshots**
If applicable, add screenshots to help explain your problem.

**Device:**
- OS: Windows
- Browser: N/A
- Version `puffin` 0.19, `puffin_http` 0.16

**Additional context**
I think this problem is related to https://github.com/EmbarkStudios/puffin/pull/169