Merge branch 'scygan_astc_fix' into 'master'

Merge branch 'scygan_astc_fix' into 'master'

pipeline.image.view_type.2d.format.astc: fix compression parameters for  ASTC formats

Looks like there is an error in tcuCompressedTexture.hpp file. Here:
TexDecompressionParams (AstcMode astcMode_ = ASTCMODE_LAST) : astcMode(astcMode_) {}
ASTCMODE_LAST is set instead of ASTCMODE_LDR.

This causes an assert in tcuCompressedTexture.cpp file:
DE_ASSERT(params.astcMode == TexDecompressionParams::ASTCMODE_LDR || params.astcMode == TexDecompressionParams::ASTCMODE_HDR);

See merge request !276