Hardcode the location of vcvars64.bat because vswhere doesn't show the VS 2022 installation path.

Author: kannanjgithub

buildscripts/kokoro/windows64.bat

@@ -17,7 +17,7 @@ set JAVA_HOME=
 
 mkdir grpc-java-helper64
 cd grpc-java-helper64
-call "%VS140COMNTOOLS%\vsvars64.bat" || exit /b 1
+call "C:\Program Files (x86)\Microsoft Visual Studio\2022\BuildTools\VC\Auxiliary\Build\vcvars64.bat" || exit /b 1
 call "%WORKSPACE%\buildscripts\make_dependencies.bat" || exit /b 1
 
 cd "%WORKSPACE%"