Fix OOB access in atomic ops

[saghul]

Fixes: #1301
Fixes: #1302

[saghul]

No idea why TCC would fail... @bnoordhuis you likely have it ready to go, mind giving it a try?

[bnoordhuis]

Atomic ops are disabled for tcc because they get miscompiled in (not so) recent versions, see 4871290. As a workaround, add something like below to tests.conf:

[features]
skip-if-tcc=!tcc

Then add a magic comment to the test file:

/*---
features: [skip-if-tcc]
---*/

[bnoordhuis]

General observation (cc @Mcsky23): ideally tests for this get submitted to https://github.com/tc39/test262 because then it trickles down to all JS engines.

[saghul]

Atomic ops are disabled for tcc because they get miscompiled in (not so) recent versions, see 4871290. As a workaround, add something like below to tests.conf:

[features]
skip-if-tcc=!tcc

Then add a magic comment to the test file:

/*---
features: [skip-if-tcc]
---*/

Got it, will do!