setBreakPointsRequest: fix synchronization issue
setBreakPointsRequest: fix synchronization issue

Remove all breakpoints first before doing anything.

ChDxterWard/vscode-janus-debug,otris/vscode-janus-debug,bkircher/vscode-janus-debug,tineheller/vscode-janus-debug,ChDxterWard/vscode-janus-debug,otris/vscode-janus-debug,tineheller/vscode-janus-debug,bkircher/vscode-janus-debug,PhilippRo/vscode-janus-debug,PhilippRo/vscode-janus-debug