Fix #1077: Deprecate Mozc_tsf_ui.log

This commit affects only mozc_tip{32,64}.dll build with debug mode.
There must be no behavior change in release build.

Currently 'Mozc_tsf_ui.log' is created only when NDEBUG is defined.
With this commit we stop creating it even when NDEBUG is defined.
This addresses a crash issue in debug builds discussed in #1077.

See #856 about why absl::LocalTimeZone cannot be used in Windows right
now.

Note that this commit may also help us diagnose #1076, where
  Windows.Storage.OneCore.dll
looks to be intercepting certain Win32 file I/O API calls in
AppContainer processes then trigger RoInitialize as needed.
Creating 'Mozc_tsf_ui.log' only in debug builds can make our debugging
more complicated.

src/win32/tip/tip_text_service.cc

@@ -150,7 +150,6 @@ constexpr GUID kTipFunctionProvider = {
 #else  // GOOGLE_JAPANESE_INPUT_BUILD
 
 constexpr char kHelpUrl[] = "https://github.com/google/mozc";
-constexpr char kLogFileName[] = "Mozc_tsf_ui.log";
 constexpr wchar_t kTaskWindowClassName[] =
     L"Mozc Immersive Task Message Window";
 
@@ -511,8 +510,6 @@ class TipTextServiceImpl
     StorePointerForCurrentThread(this);
 
     HRESULT result = E_UNEXPECTED;
-    RegisterLogFileSink(
-        FileUtil::JoinPath(SystemUtil::GetLoggingDirectory(), kLogFileName));
 
     EnsureKanaLockUnlocked();