String case conversion is known to debug-evaluate to not have a side
effect in noi18n mode, but debug-evaluate thinks it has a side effect
in i18n mode. Update the tests accordingly.

Verified locally that the test passes in i18n and noi18n mode (not sure
whether the noi18n trybot executes this test).

CQ_INCLUDE_TRYBOTS=master.tryserver.v8:v8_linux_noi18n_rel_ng

Review-Url: https://codereview.chromium.org/2750403004
Cr-Commit-Position: refs/heads/master@{#43882}