Find in terminal clears result highlight if there is only a single result and you press enter again

[mjbvz]

Issue Type: Bug

steps

1. In VS Code source
2. Open a new integrated terminal
3. Run ls
4. Search for OSS in the terminal
5. Press enter and see one result for OSSREADME.jsoncorrectly highlighted
6. Now Press enter multiple times

Bug
The highlighting of the result is lost

VS Code version: Code - Insiders 1.29.0-insider (97ad72a, 2018-10-31T06:11:22.318Z)
OS version: Darwin x64 18.0.0

System Info

Item	Value
CPUs	Intel(R) Core(TM) i7-4770HQ CPU @ 2.20GHz (8 x 2200)
GPU Status	2d_canvas: enabled checker_imaging: disabled_off flash_3d: enabled flash_stage3d: enabled flash_stage3d_baseline: enabled gpu_compositing: enabled multiple_raster_threads: enabled_on native_gpu_memory_buffers: enabled rasterization: enabled video_decode: enabled video_encode: enabled webgl: enabled webgl2: enabled
Load (avg)	4, 3, 3
Memory (System)	16.00GB (0.03GB free)
Process Argv
Screen Reader	no
VM	22%

[Tyriar]

Upstream issue: xtermjs/xterm.js#2456