Remove time-dependent test from coverage measurements
Remove time-dependent test from coverage measurements

Compiling with coverage enabled screws up the time that things take, so
don't test for a particular speedup in that case. It fails unreliably.

BUG=chrome-os-partner:20881
BRANCH=ToT
TEST=manual

  cd src/platform/ec
  make coverage

Before, it failed about half the time. Now it doesn't.

Change-Id: I535f0193bf450a922b486777b296fea1b2768a1a
Signed-off-by: Bill Richardson <129945214b1d548d8e49b6c29c43094f8c78057f@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/188790
Reviewed-by: Randall Spangler <62698fdbb84d1779579ee80c3f39fac22017e5bc@chromium.org>

coreboot/chrome-ec,thehobn/ec,coreboot/chrome-ec,mtk09422/chromiumos-platform-ec,gelraen/cros-ec,coreboot/chrome-ec,longsleep/ec,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,md5555/ec,eatbyte/chromium-ec,fourier49/BZ_DEV_EC,gelraen/cros-ec,fourier49/BIZ_EC,alterapraxisptyltd/chromium-ec,alterapraxisptyltd/chromium-ec,fourier49/BIZ_EC,akappy7/ChromeOS_EC_LED_Diagnostics,akappy7/ChromeOS_EC_LED_Diagnostics,coreboot/chrome-ec,akappy7/ChromeOS_EC_LED_Diagnostics,gelraen/cros-ec,eatbyte/chromium-ec,fourier49/BZ_DEV_EC,akappy7/ChromeOS_EC_LED_Diagnostics,longsleep/ec,fourier49/BZ_DEV_EC,longsleep/ec,thehobn/ec,eatbyte/chromium-ec,alterapraxisptyltd/chromium-ec,md5555/ec,eatbyte/chromium-ec,mtk09422/chromiumos-platform-ec,md5555/ec,longsleep/ec,coreboot/chrome-ec,mtk09422/chromiumos-platform-ec,md5555/ec,thehobn/ec,fourier49/BIZ_EC,alterapraxisptyltd/chromium-ec,thehobn/ec,fourier49/BZ_DEV_EC,fourier49/BIZ_EC,gelraen/cros-ec,mtk09422/chromiumos-platform-ec