Prefer /usr/bin/env xxx over /usr/bin/xxx where xxx = perl, python, awk

Allow users to use a non-system version of perl, python and awk, which is useful
in certain package managers.

Reviewed By: JDevlieghere, MaskRay

Differential Revision: https://reviews.llvm.org/D95119

GitOrigin-RevId: a54f160b3a98b91cd241a555d904a6b6453affc4
diff --git a/llgdb-tests/test_debuginfo.pl b/llgdb-tests/test_debuginfo.pl
index e4c2a5e..23d2304 100755
--- a/llgdb-tests/test_debuginfo.pl
+++ b/llgdb-tests/test_debuginfo.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 #
 # This script tests debugging information generated by a compiler.
 # Input arguments