feat: add support for v8 version 10+

[dios-david]

After upgrading from Node 16 to Node 18 I noticed that I get some undefineds in the gctype label in my prometheus metrics:

koa_nodejs_gc_runs_total{gctype="Scavenge"} 3618
koa_nodejs_gc_runs_total{gctype="WeakPhantom"} 482
koa_nodejs_gc_runs_total{gctype="IncrementalMarking"} 241
koa_nodejs_gc_runs_total{gctype="undefined"} 2877

After digging into this a bit, I found out that the GCType enum was changed in v8 in version 10 in this PR (check deps/v8/include/v8-callbacks.h):

Before:
https://github.com/nodejs/node/blob/554fa24916c5c6d052b51c5cee9556b76489b3f7/deps/v8/include/v8.h#L6137-L6144

enum GCType {
  kGCTypeScavenge = 1 << 0,
  kGCTypeMarkSweepCompact = 1 << 1,
  kGCTypeIncrementalMarking = 1 << 2,
  kGCTypeProcessWeakCallbacks = 1 << 3,
  kGCTypeAll = kGCTypeScavenge | kGCTypeMarkSweepCompact |
               kGCTypeIncrementalMarking | kGCTypeProcessWeakCallbacks
};

After:
https://github.com/nodejs/node/blob/main/deps/v8/include/v8-callbacks.h#L150-L159

enum GCType {
  kGCTypeScavenge = 1 << 0,
  kGCTypeMinorMarkCompact = 1 << 1,
  kGCTypeMarkSweepCompact = 1 << 2,
  kGCTypeIncrementalMarking = 1 << 3,
  kGCTypeProcessWeakCallbacks = 1 << 4,
  kGCTypeAll = kGCTypeScavenge | kGCTypeMinorMarkCompact |
               kGCTypeMarkSweepCompact | kGCTypeIncrementalMarking |
               kGCTypeProcessWeakCallbacks
};

I made some changes to be able to support both 10+ and <10 versions of v8 with proper GC type mappings.

Let me know what you think.

[dios-david]

@SimenB fyi

[SimenB]

thanks!

[SimenB]

https://github.com/SimenB/node-prometheus-gc-stats/releases/tag/v0.6.4