[yugabyte#7848] Fix for yb-prof for python3

Summary: Making yb-prof py3 compatible.

Test Plan: `./bin/yb-prof.py --profile_url=localhost:9000/pprof --output_file_prefix=/tmp/bogdan_test/512_tablets --seconds=30`

Reviewers: amitanand, rahuldesirazu, kannan

Reviewed By: kannan

Subscribers: ybase

Differential Revision: https://phabricator.dev.yugabyte.com/D11081

bin/yb-prof.py

@@ -104,7 +104,7 @@ def symbolize(self, symbols):
            "-d",
            arg,
            self.pprof_url_ + "/symbol"])
-        lines = result.split("\n")
+        lines = result.decode().split("\n")
         for line in lines:
             # Use whitespace as the delimiter, and produce no more than two parts
             # (i.e. max of 1 split). The symbolized function name may itself contain