[compiler-rt] Unify python shebangs (#187285)

As per PEP-0394[1], there is no real concensus over what binary names
Python has, specifically 'python' could be Python 3, Python 2, or not
exist.

However, everyone has a python3 interpreter and the scripts are all
written for Python 3. Unify the shebangs so that the ~50% of shebangs
that use python now use python3.

[1] https://peps.python.org/pep-0394/

GitOrigin-RevId: 015e3d2b20924e966345d3c493fb16f2fa3160b4

scripts/unbalanced_allocs.py

diff --git a/scripts/unbalanced_allocs.py b/scripts/unbalanced_allocs.py
index 7ba7e09..c8c19a0 100755
--- a/scripts/unbalanced_allocs.py
+++ b/scripts/unbalanced_allocs.py
@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # ===- lib/fuzzer/scripts/unbalanced_allocs.py ------------------------------===#
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.