v8 gc-tracer-inl debug assertion: IsMainThread

Title: v8 gc-tracer-inl debug assertion: IsMainThread

Description: We are seeing a debug assertion triggered when using WASM with debug build:

#
# Fatal error in external/v8/src/heap/gc-tracer-inl.h, line 60
# Debug check failed: tracer_->heap_->IsMainThread() || tracer_->heap_->IsSharedMainThread().
#
#
#
#FailureMessage Object: 0x7f37cccc3c60
==== C stack trace ===============================

    /usr/local/bin/envoy(+0x9534fee) [0x555d4cc24fee]
    /usr/local/bin/envoy(+0x8a8603e) [0x555d4c17603e]
    /usr/local/bin/envoy(+0x9511fca) [0x555d4cc01fca]
    /usr/local/bin/envoy(+0x951196c) [0x555d4cc0196c]
    /usr/local/bin/envoy(+0x9512067) [0x555d4cc02067]
    /usr/local/bin/envoy(+0x6d68756) [0x555d4a458756]
    /usr/local/bin/envoy(+0x6e6e12b) [0x555d4a55e12b]
    /usr/local/bin/envoy(+0x6e6d569) [0x555d4a55d569]
    /usr/local/bin/envoy(+0x6e703a0) [0x555d4a5603a0]
    /usr/local/bin/envoy(+0x6434d11) [0x555d49b24d11]
    /usr/local/bin/envoy(+0x64350fa) [0x555d49b250fa]
    /usr/local/bin/envoy(+0x642df3b) [0x555d49b1df3b]
    /usr/local/bin/envoy(+0x642debc) [0x555d49b1debc]
    /usr/local/bin/envoy(+0x63f94f9) [0x555d49ae94f9]
    /usr/local/bin/envoy(+0x63fa912) [0x555d49aea912]
    /usr/local/bin/envoy(+0x63fa949) [0x555d49aea949]
    /usr/local/bin/envoy(+0x5dbfd2c) [0x555d494afd2c]
    /usr/local/bin/envoy(+0x5dbfcac) [0x555d494afcac]
    /usr/local/bin/envoy(+0x5db7d19) [0x555d494a7d19]
    /usr/local/bin/envoy(+0x63d3802) [0x555d49ac3802]
    /usr/local/bin/envoy(+0x5da0ae3) [0x555d49490ae3]
    /usr/local/bin/envoy(+0x5dbb1cd) [0x555d494ab1cd]
    /usr/local/bin/envoy(+0xcdaf24e) [0x555d5049f24e]
    /usr/local/bin/envoy(+0x5db7a6c) [0x555d494a7a6c]
    /usr/local/bin/envoy(+0x5dbbfdd) [0x555d494abfdd]
    /usr/local/bin/envoy(+0x5dbbe91) [0x555d494abe91]
    /usr/local/bin/envoy(+0x5dbbcad) [0x555d494abcad]
    /usr/local/bin/envoy(+0xcdaf24e) [0x555d5049f24e]
    /usr/local/bin/envoy(+0x5db82fc) [0x555d494a82fc]
    /usr/local/bin/envoy(+0x63d353b) [0x555d49ac353b]
    /usr/local/bin/envoy(+0x5da0ae3) [0x555d49490ae3]
    /usr/local/bin/envoy(+0x5dbb1cd) [0x555d494ab1cd]
    /usr/local/bin/envoy(+0xcdaf24e) [0x555d5049f24e]
    /usr/local/bin/envoy(+0x5db7a6c) [0x555d494a7a6c]
    /usr/local/bin/envoy(+0x5dbbfdd) [0x555d494abfdd]
    /usr/local/bin/envoy(+0x5dbbe91) [0x555d494abe91]
    /usr/local/bin/envoy(+0x5dbbcad) [0x555d494abcad]
    /usr/local/bin/envoy(+0xcdaf24e) [0x555d5049f24e]
    /usr/local/bin/envoy(+0x5db82fc) [0x555d494a82fc]
    /usr/local/bin/envoy(+0x5dbd7bc) [0x555d494ad7bc]
    /usr/local/bin/envoy(+0x5dbd6d3) [0x555d494ad6d3]
    /usr/local/bin/envoy(+0x5dbd45d) [0x555d494ad45d]
    /usr/local/bin/envoy(+0xcdaf24e) [0x555d5049f24e]
    /usr/local/bin/envoy(+0x4db28cc) [0x555d484a28cc]
    /usr/local/bin/envoy(+0x4db68bb) [0x555d484a68bb]
    /usr/local/bin/envoy(+0x4db67cd) [0x555d484a67cd]
    /usr/local/bin/envoy(+0xcdaf24e) [0x555d5049f24e]
    /usr/local/bin/envoy(+0x4d13dfc) [0x555d48403dfc]
    /usr/local/bin/envoy(+0x9e47243) [0x555d4d537243]
    /usr/local/bin/envoy(+0x9e4105d) [0x555d4d53105d]
    /usr/local/bin/envoy(+0x9e40fcd) [0x555d4d530fcd]
    /usr/local/bin/envoy(+0x9e40f7d) [0x555d4d530f7d]
    /usr/local/bin/envoy(+0x9e40f4d) [0x555d4d530f4d]
    /usr/local/bin/envoy(+0x9e40099) [0x555d4d530099]
    /usr/local/bin/envoy(+0x4a523e2) [0x555d481423e2]
    /usr/local/bin/envoy(+0x4a523a5) [0x555d481423a5]
    /usr/local/bin/envoy(+0xb8c4c9d) [0x555d4efb4c9d]
    /usr/local/bin/envoy(+0xb8cd2b8) [0x555d4efbd2b8]
    /usr/local/bin/envoy(+0xb8cd27d) [0x555d4efbd27d]
    /usr/local/bin/envoy(+0xb8cd22d) [0x555d4efbd22d]
    /usr/local/bin/envoy(+0xb8cd1fd) [0x555d4efbd1fd]
    /usr/local/bin/envoy(+0xb8cc349) [0x555d4efbc349]

Repro steps: Use V8 WASM with debug build. I can try to reduce to a concrete Envoy config example if needed and when I find time