Support consistent lookup of Java location in Controller and Agent start scripts for Windows

Current Situation 

• The controller.cmd and agent.cmd start scripts implement:

  set JAVABIN=java.exe
  if exist "%JAVA_HOME%\bin\java.exe" set JAVABIN=%JAVA_HOME%\bin\java.exe
  

• At the same time, the scripts call Java from its name like this:
  • Controller: controller.cmd

    for /f "usebackq" %%i in (`java -classpath "%JS7_CONTROLLER_LIBDIR%/classes" DefaultTimeZone 2^>nul`) do set JS7_CONTROLLER_TZ=%%i
    

• • Agent: agent.cmd

    for /f "usebackq" %%i in (`java -classpath "%JS7_AGENT_LIBDIR%/classes" DefaultTimeZone 2^>nul`) do set JS7_AGENT_TZ=%%i
    

• This allows inconsistent use of Java locations if more than one Java version is available with the desired version being specified by the JAVA_HOME environment variable and the undesired version by the PATH environment variable.

Desired Behavior

• The controller.cmd and agent.cmd start scripts should replace

  `java -classpath
  

    by

  `%JAVABIN% -classpath