Fixes running x64 binaries on arm64 hosts, this fixes systems like Raspberry Pi's, Apple Silicon, and Ampere.
Before, I would get something like:
```
Checking GN formatting...
Completed checking 0 GN files with no formatting problems.
Checking Java formatting...
No Java files with changes, skipping Java format check.
Checking Python formatting...
All python files formatted correctly.
Checking for trailing whitespace on 1 source file...
No trailing whitespace found.
No header files with changes, skipping header guard check.
Checking C++/ObjC/Shader formatting...
ERROR: Formatter command '/home/ross/flutter-engine/src/flutter/buildtools/linux-x64/clang/bin/clang-format --style=file shell/platform/linux/fl_application_test.cc' failed with exit code 255. Command output follows:
qemu-x86_64: Could not open '/lib64/ld-linux-x86-64.so.2': No such file or directory
Completed checking 0 C++/ObjC/Shader files with no formatting problems
```
Now it just works, I also changed the shell script to use env since `/bin/bash` doesn't exist on NixOS so using env is a more portable solution.
*List which issues are fixed by this PR. You must list at least one issue.*
*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*
[C++, Objective-C, Java style guides]: https://github.com/flutter/engine/blob/main/CONTRIBUTING.md#style
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