Ensure Win JSC can run complex.yaml tests

https://bugs.webkit.org/show_bug.cgi?id=255078

Reviewed by Yusuke Suzuki.

Making this test suite work on Windows boils down to fixing two problems:

1. The tests which don't set env vars are passing an empty string, but in Ruby, this is appended to a list ($envVars),
   meaning that we end up trying to set a env var with key "". Use nil instead.

2. On Windows, TZ isn't a magic env var, so:
   a. Have jsc.cpp call setTimeZoneOverride instead.
   b. Skip temporal-now-timezone-with-broken-tz.js.
      (Obviously we could call setTimeZoneOverride with "UTC" if (a) fails,
      but it would serve no purpose, as this behavior has nothing to do with Temporal.)

* JSTests/complex.yaml:
* Source/JavaScriptCore/jsc.cpp:

Canonical link: https://commits.webkit.org/262659@main

JSTests/complex.yaml

@@ -24,10 +24,10 @@
 # This is for writing a bit complex tests to drive in JSC shell (e.g. including multiple files with some special options).
 
 - path: complex/generator-regeneration.js
-  cmd: runComplexTest [], ["generator-regeneration-after.js"], "", "--useDollarVM=1"
+  cmd: runComplexTest [], ["generator-regeneration-after.js"], nil, "--useDollarVM=1"
 
 - path: complex/tagged-template-regeneration.js
-  cmd: runComplexTest [], ["tagged-template-regeneration-after.js"], "", "--useDollarVM=1"
+  cmd: runComplexTest [], ["tagged-template-regeneration-after.js"], nil, "--useDollarVM=1"
 
 - path: complex/timezone-format-de.js
   cmd: runComplexTest [], [], "TZ=Europe/Berlin", "--useDollarVM=1"
@@ -57,10 +57,15 @@
   cmd: runComplexTest [], [], "TZ=America/Los_Angeles", "--useDollarVM=1", "--useTemporal=1"
 
 - path: complex/temporal-now-timezone-with-broken-tz.js
-  cmd: runComplexTest [], [], "TZ=UNDEFINED", "--useDollarVM=1", "--useTemporal=1"
+  cmd: |
+      if ($hostOS == "windows")
+          skip
+      else
+          runComplexTest [], [], "TZ=UNDEFINED", "--useDollarVM=1", "--useTemporal=1"
+      end
 
 - path: complex/for-in-clobberize.js
-  cmd: runComplexTest [], [], "", "--destroy-vm"
+  cmd: runComplexTest [], [], nil, "--destroy-vm"
 
 - path: complex/intl-date-time-format-date-parse.js
   cmd: runComplexTest [], [], "TZ=America/New_York"

Source/JavaScriptCore/jsc.cpp

@@ -3961,8 +3961,13 @@ int jscmain(int argc, char** argv)
     // comes first.
     mainCommandLine.construct(argc, argv);
 
-#if OS(UNIX)
+#if OS(WINDOWS)
+    // Needed for complex.yaml tests.
+    if (char* tz = getenv("TZ"))
+        setTimeZoneOverride(StringView::fromLatin1(tz));
+#endif
 
+#if OS(UNIX)
     if (getenv("JS_SHELL_WAIT_FOR_SIGUSR2_TO_EXIT")) {
         initializeSignalHandling();
         addSignalHandler(Signal::Usr, SignalHandler([&] (Signal, SigInfo&, PlatformRegisters&) {