DevTools: cleanup debugger tests.

LayoutTests/inspector/sources/debugger/debugger-scripts-expected.txt

 Tests that valid parsed script notifications are received by front-end. Bug 52721
 
-Debugger was enabled.
 script 1:
     start: 5:8
     end: 38:0
 script 2:
     start: 38:21
     end: 42:0
 script 3:
     start: 43:11
     end: 43:32
 script 4:
     start: 44:11
     end: 45:0
 script 5:
     start: 46:11
     end: 48:0
 script 6:
     start: 51:56
     end: 52:7
-Debugger was disabled.