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/runtime/tools/check-execstack.pl b/runtime/tools/check-execstack.pl
index e4a8e7c..7a71007 100755
--- a/runtime/tools/check-execstack.pl
+++ b/runtime/tools/check-execstack.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 #
 #//===----------------------------------------------------------------------===//
diff --git a/runtime/tools/check-instruction-set.pl b/runtime/tools/check-instruction-set.pl
index 65c315d..6edfb55 100755
--- a/runtime/tools/check-instruction-set.pl
+++ b/runtime/tools/check-instruction-set.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 #
 #//===----------------------------------------------------------------------===//
diff --git a/runtime/tools/message-converter.pl b/runtime/tools/message-converter.pl
index b3efb70..22b87c0 100755
--- a/runtime/tools/message-converter.pl
+++ b/runtime/tools/message-converter.pl
@@ -1,4 +1,4 @@
-#!/usr/bin/perl
+#!/usr/bin/env perl
 
 #
 #//===----------------------------------------------------------------------===//