testscripts:
1.optimize code
2.convert the input path to absolute path
3.test h264 encode with h264 folder. test 10 specific h264 files, if there is no these files, select 10 random h264 files.
v4l2: fix mistake when using fewer number of outputbuffer

fix the random ASSERT fail of v4l2decode
tests: DecodeStreamOutputDmabuf refine, use createEglImageFromHandle
tests: distinguish external texture (dma_buf) required by glsl shader

dma_buf texture is considered as external buffer in mesa,
it requires 'samplerExternalOES' in glsl shader