Fix msvc utf-8

[longhuan2018]

Solve the errors caused by utf-8 encoding under Chinese windows operating system, using msvc compilation

[nyalldawson]

This change has broken some tests -- see https://dev.azure.com/qgis/QGIS/_build/results?buildId=4098&view=ms.vss-test-web.build-test-results-tab. Are you able to investigate please?

[longhuan2018]

This change has broken some tests -- see https://dev.azure.com/qgis/QGIS/_build/results?buildId=4098&view=ms.vss-test-web.build-test-results-tab. Are you able to investigate please?

https://doc.qt.io/qt-5/qstring.html#QStringLiteral

Note: Some compilers have bugs encoding strings containing characters outside the US-ASCII character set. Make sure you prefix your string with u in those cases. It is optional otherwise.

[nyalldawson]

Thanks! Let's see if this round passes