Electron 4.0.x: build failures in integration test on macOS

[bpasero]

There are still some sporadic native crashes on our integration tests on macOS:

• https://dev.azure.com/vscode/VSCode/_build/results?buildId=21367
• https://dev.azure.com/vscode/VSCode/_build/results?buildId=21364

After emmet tests:

Electron(2642,0x7fffa44a6380) malloc: *** error for object 0x7fbe60759b90: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
Received signal 6
 [0x000102c2ed2c]
 [0x000102c2ec11]
 [0x7fff6c092f5a]
 [0x000000000000]
 [0x7fff6be301ae]
 [0x7fff6bf2e8a6]
 [0x0001021b0f0c]
 [0x000105c21604]
 [0x000105c208b3]
 [0x000105ca880b]
 [0x000105cb860d]
 [0x000105ca8c63]
 [0x000105b8aca6]
 [0x000105b8b019]
 [0x000105ba57ae]
 [0x000102aca568]
 [0x000102aca63e]
 [0x0001017dd929]
 [0x0001017dda3e]
 [0x0001017e3741]
 [0x0001017dd454]
 [0x000102a35bf8]
 [0x000103e2ad5d]
 [0x000102a34ca4]
 [0x000100dd3654]
 [0x000100dccf10]
 [0x7fff6bd84015]
[end of stack trace]
./scripts/test-integration.sh: line 25:  2642 Abort trap: 6           ./scripts/code.sh $ROOT/extensions/emmet/test-fixtures --extensionDevelopmentPath=$ROOT/extensions/emmet --extensionTestsPath=$ROOT/extensions/emmet/out/test --disable-extensions --skip-getting-started --disable-inspect --user-data-dir=$VSCODEUSERDATADIR
##[error]Bash exited with code '134'.
##[section]Finishing: Run Integration Tests