macos: add --jitless to fix V8 CodeRange OOM in --single-process mode

--single-process runs the renderer's V8 in the browser process, which
requires a large contiguous virtual memory reservation for JIT code
(CodeRange). On older macOS-14 CI runner images this reservation fails:

  V8 process OOM (Failed to reserve virtual memory for CodeRange)

--jitless disables all V8 JIT compilers (Sparkplug, Maglev, Turbofan),
eliminating the CodeRange requirement entirely. Unit test JS is simple
enough that interpreted execution is sufficient.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

Author: linesight

unittests/main_test.py

@@ -193,6 +193,12 @@ def test_main(self):
             # --single-process runs the renderer in the browser process,
             # eliminating renderer subprocess bootstrap_look_up failures.
             switches["single-process"] = ""
+            # --single-process puts the renderer's V8 in the browser process,
+            # which requires a large contiguous CodeRange for JIT code.
+            # On constrained CI runner images this reservation fails with an
+            # OOM error.  --jitless disables all V8 JIT compilers, eliminating
+            # the CodeRange requirement entirely.
+            switches["js-flags"] = "--jitless"
             # Run network service in-process to avoid Mach port rendezvous
             # failures for utility subprocesses on macOS CI runners.
             # The feature string in Chrome 130+ is "NetworkServiceInProcess2".

unittests/osr_test.py

@@ -151,6 +151,12 @@ def test_osr(self):
             # --single-process runs the renderer in the browser process,
             # eliminating renderer subprocess bootstrap_look_up failures.
             switches["single-process"] = ""
+            # --single-process puts the renderer's V8 in the browser process,
+            # which requires a large contiguous CodeRange for JIT code.
+            # On constrained CI runner images this reservation fails with an
+            # OOM error.  --jitless disables all V8 JIT compilers, eliminating
+            # the CodeRange requirement entirely.
+            switches["js-flags"] = "--jitless"
             # Run network service in-process to avoid Mach port rendezvous
             # failures for utility subprocesses on macOS CI runners.
             # The feature string in Chrome 130+ is "NetworkServiceInProcess2".