test: lib_helper: Remove inline python

Using jq instead of python means we don't have to worry about py2 vs py3
incompatibilities.

Change-Id: Idabd488dc4e02250650d2eccece42968d993715a

test/lib/lib_helper.sh

diff --git a/test/lib/lib_helper.sh b/test/lib/lib_helper.sh
index 573ed10..3e6f0b5 100644
--- a/test/lib/lib_helper.sh
+++ b/test/lib/lib_helper.sh
@@ -145,9 +145,7 @@
 # ---- JSON PARSING ----
 
 json_pp() { # < json > json
-    python -c "import sys, json; \
-            print json.dumps(json.loads(sys.stdin.read()), indent=3, \
-            separators=(',', ' : '), sort_keys=True)"
+    jq --indent 3 --sort-keys
 }
 
 json_val_by_key() {  # json key > value