windows: Configure stack size for executables (fixes issue #3250)

Change the default stack size to 8 MiB for 64-bit and 0.5 MiB for 32-bit.

CEF's main thread needs at least a 1.5 MiB stack size in order to avoid
stack overflow crashes. However, if this is set in the PE file then other
threads get this size as well, leading to address-space exhaustion in 32-bit
CEF. A new CefRunWinMainWithPreferredStackSize function uses fibers to switch
the main thread to a 4 MiB stack (roughly the same effective size as the
64-bit build's 8 MiB stack) before running any other code.

This change additionally moves the existing Windows-only functions
CefSetOSModalLoop and CefEnableHighDPISupport from cef_app.h to cef_win.h.

tools/cef_api_hash.py

@@ -40,6 +40,7 @@ class cef_api_hash:
     self.platform_files = {
         # List of includes_win_capi from cef_paths2.gypi.
         "windows": [
+            "internal/cef_app_win.h",
             "internal/cef_types_win.h",
         ],
         # List of includes_mac_capi from cef_paths2.gypi.