Do not compile webrtc_lib_link_test if is_asan=true.
Do not compile webrtc_lib_link_test if is_asan=true.

This should avoid to get errors like the ones below when is_asan=true
and target_os="mac":

warning: (x86_64)  could not find object file symbol for symbol _write_mb_features
warning: (x86_64)  could not find object file symbol for symbol _update_mode
warning: (x86_64)  could not find object file symbol for symbol _vp8cx_base_skip_false_prob
warning: (x86_64)  could not find object file symbol for symbol _default_coef_counts
warning: (x86_64)  could not find object file symbol for symbol _vpx_skin_pixel

Bug: webrtc:11027
Change-Id: Iebcb55a43d1ed5c8d1ce43d456c0e83ffa5cc2c1
Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/158000
Commit-Queue: Mirko Bonadei <d2c43c210eae6feef04f53bae50885e8152edcca@webrtc.org>
Reviewed-by: Patrik Höglund <b486136ee68458b09c92c86c39f451c87d6ef6a1@webrtc.org>
Cr-Commit-Position: 972c6d2dc6dd5efdad1377c0d224e03eb8f276f7@{#29587}

TimothyGu/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc,TimothyGu/libilbc,ShiftMediaProject/libilbc,ShiftMediaProject/libilbc