targets/stm32f730r8tx_arduino: Switch to assert_log

This saves 1920 of flash space.

Before:
  FLASH: 55852 B  64 KB  85.22%

After:
  FLASH: 53932 B  64 KB  82.29%

Change-Id: I5156a2c9a3d82393595877a91463547a9bb6e4ec
Reviewed-on: https://pigweed-review.googlesource.com/c/gonk/+/190070
Commit-Queue: Anthony DiGirolamo <tonymd@google.com>
Reviewed-by: Eric Holland <hollande@google.com>
Presubmit-Verified: CQ Bot Account <pigweed-scoped@luci-project-accounts.iam.gserviceaccount.com>

targets/stm32f730r8tx_arduino/target_toolchains.gni

diff --git a/targets/stm32f730r8tx_arduino/target_toolchains.gni b/targets/stm32f730r8tx_arduino/target_toolchains.gni
index 0522cd0..b0fe0e2 100644
--- a/targets/stm32f730r8tx_arduino/target_toolchains.gni
+++ b/targets/stm32f730r8tx_arduino/target_toolchains.gni
@@ -43,7 +43,7 @@
   }
 
   # Facade backends
-  pw_assert_BACKEND = dir_pw_assert_basic
+  pw_assert_BACKEND = dir_pw_assert_log
   pw_log_BACKEND = dir_pw_log_basic
   pw_sync_INTERRUPT_SPIN_LOCK_BACKEND =
       "$dir_pw_sync_baremetal:interrupt_spin_lock"