[clang] Use portable "#!/usr/bin/env bash" shebang for tools and utils.

[JDevlieghere]

LGTM

[xgupta]

I can push this for you @fcambus.

[fcambus]

I can push this for you @fcambus.

Thanks for committing this. I also have a similar diff for compiler-rt, in D110039.

clang/tools/diag-build/diag-build.sh

-#!/bin/bash
+#!/usr/bin/env bash
 
 # diag-build: a tool showing enabled warnings in a project.
 #
 # diag-build acts as a wrapper for 'diagtool show-enabled', in the same way
 # that scan-build acts as a wrapper for the static analyzer. The common case is
 # simple: use 'diag-build make' or 'diag-build xcodebuild' to list the warnings
 # enabled for the first compilation command we see. Other build systems require
 # you to manually specify "dry-run" and "use $CC and $CXX"; if there is a build

clang/utils/make-ast-dump-check.sh

-#! /bin/bash
+#!/usr/bin/env bash
 
 # This script is intended as a FileCheck replacement to update the test
 # expectations in a -ast-dump test.
 #
 # Usage (to generate normal AST dump tests):
 #
 # $ lit -DFileCheck=$PWD/utils/make-ast-dump-check.sh test/AST/ast-dump-openmp-*
 #