T-API: cv::flip optimization for CV_8UC1

merge after https://github.com/Itseez/opencv/pull/2757

check_regression=*OCL*Flip*
test_modules=core
test_filter=*OCL*Flip*
build_examples=OFF

New approach with compare to the previous one:
```
Flip::OCL_FlipFixture::(640x480, 8UC1, FLIP_BOTH)    0.230 ms  0.194 ms     1.19
Flip::OCL_FlipFixture::(640x480, 8UC1, FLIP_COLS)    0.212 ms  0.149 ms     1.42
Flip::OCL_FlipFixture::(640x480, 8UC1, FLIP_ROWS)    0.210 ms  0.158 ms     1.33
Flip::OCL_FlipFixture::(1280x720, 8UC1, FLIP_BOTH)   0.299 ms  0.221 ms     1.35
Flip::OCL_FlipFixture::(1280x720, 8UC1, FLIP_COLS)   0.289 ms  0.195 ms     1.48
Flip::OCL_FlipFixture::(1280x720, 8UC1, FLIP_ROWS)   0.287 ms  0.213 ms     1.35
Flip::OCL_FlipFixture::(1920x1080, 8UC1, FLIP_BOTH)  0.330 ms  0.202 ms     1.63
Flip::OCL_FlipFixture::(1920x1080, 8UC1, FLIP_COLS)  0.319 ms  0.205 ms     1.55
Flip::OCL_FlipFixture::(1920x1080, 8UC1, FLIP_ROWS)  0.323 ms  0.228 ms     1.42
Flip::OCL_FlipFixture::(3840x2160, 8UC1, FLIP_BOTH)  1.553 ms  0.916 ms     1.70
Flip::OCL_FlipFixture::(3840x2160, 8UC1, FLIP_COLS)  1.613 ms  0.870 ms     1.85
Flip::OCL_FlipFixture::(3840x2160, 8UC1, FLIP_ROWS)  1.606 ms  0.852 ms     1.89
```