Decode standard output when recompilation fails

BUG=none
TEST=make compilation of mttools/mtreplay fail, then run the tests

Change-Id: Iff5efb7a2ad09604e4cfe3589c3618c31c925501
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/touchpad-tests/+/2314861
Tested-by: Harry Cutts <hcutts@chromium.org>
Auto-Submit: Harry Cutts <hcutts@chromium.org>
Reviewed-by: Sean O'Brien <seobrien@chromium.org>
Commit-Queue: Sean O'Brien <seobrien@chromium.org>
diff --git a/framework/src/main.py b/framework/src/main.py
index 308a590..780ac74 100644
--- a/framework/src/main.py
+++ b/framework/src/main.py
@@ -99,7 +99,7 @@
                   "in-place"], cwd=dir, stdout=PIPE, stderr=STDOUT)
   ret = process.wait()
   if ret != 0:
-    print(process.stdout.read())
+    print(process.stdout.read().decode(errors='replace'))
     sys.exit(1)