Install Mozc into `%ProgramFiles%\Mozc` rather than `%ProgramFiles(x86)%\Mozc`

[yukawa]

Description

Historically we have been installing Mozc into %ProgramFiles(x86)%\Mozc (e.g. C:\Program Files (x86)\Mozc) rather than %ProgramFiles%\Mozc even on 64-bint environment as that is how Google Japanese Input has been doing since 2009.

This is going to be much more confusing when we start supporting Windows Arm64 environment, where we may see the following 3 "Program Files" directories.

• C:\Program Files: 64-bit binaries for both Arm64 and x86_64
• C:\Program Files (Arm): arm 32-bit binaries
• C:\Program Files (x86): x86 32-bit binaries

Let's see if we can migrate from %ProgramFiles(x86)%\Mozc to %ProgramFiles%\Mozc without disturbing existing (Google Japanese Input) users, as one of preparations to support Windows Arm64 environments.

Steps to reproduce

Steps to reproduce the behavior:

1. Install some older version of Mozc, which is to be installed into %ProgramFiles(x86)%\Mozc.
2. Launch some app and select Mozc.
3. Build a new version of Mozc, which is to be installed into %ProgramFiles%\Mozc.
4. msiexec.exe /i Mozc64.msi /qn REBOOT=ReallySuppress

Screenshots

Mozc continues working on the app launched at the step 2.

Version or commit-id

8c8a446

Environment

• OS: Windows 11 23H2

Additional context

• Improper installation location for 64-bit version on Windows? #732
• Improper installation location for 64-bit version on Windows? #893