[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/

compiler-rt/lib/asan/scripts/asan_symbolize.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # ===- lib/asan/scripts/asan_symbolize.py -----------------------------------===#
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

compiler-rt/lib/fuzzer/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.

compiler-rt/lib/sanitizer_common/scripts/gen_dynamic_list.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # ===- lib/sanitizer_common/scripts/gen_dynamic_list.py ---------------------===#
 #
 # Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.

compiler-rt/lib/sanitizer_common/scripts/sancov.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 # Merge or print the coverage data collected by asan's coverage.
 # Input files are sequences of 4-byte integers.
 # We need to merge these integers into a set and then