Test opts file reader to cover issue #2140

[lefou]

Tried to reproduce #2140, which claims, we miss the last option when the opts file does not end with a newline.

Can't reproduce locally.

Here is a hex dump of the file added:

$ hexdump -C main/client/test/resources/file-wo-final-newline.txt
00000000  0a 23 20 63 6f 6d 6d 65  6e 74 20 61 66 74 65 72  |.# comment after|
00000010  20 61 6e 20 65 6d 70 74  79 20 6c 69 6e 65 0a 2d  | an empty line.-|
00000020  44 50 52 4f 50 45 52 54  59 5f 50 52 4f 50 45 52  |DPROPERTY_PROPER|
00000030  4c 59 5f 53 45 54 5f 56  49 41 5f 4a 56 4d 5f 4f  |LY_SET_VIA_JVM_O|
00000040  50 54 53 3d 76 61 6c 75  65 2d 66 72 6f 6d 2d 66  |PTS=value-from-f|
00000050  69 6c 65 0a 2d 58 73 73  31 32 30 6d              |ile.-Xss120m|
0000005c