[code-reflection] RFR: Dont use hashbang for launcher scripts

[Gary Frost]

Pivoted away from using shebang/hashbang for `bld`, `sanity` and `hatrun` scripts. 

This was not really portable (clearly will not work on Windows) and also forced env.bash to precompile bldr/../Bldr.java

Now we rely on these scripts being launched using 


java bldr/@args bld 
``` 

Which relies on JEP 458 to launch 'multi source' to  pick up Bldr.java

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Commit messages:
 - Dont use hashbang for launcher scripts
 - Dont use hashbang for launcher scripts

Changes: https://git.openjdk.org/babylon/pull/268/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=268&range=00
  Stats: 105 lines in 8 files changed: 34 ins; 49 del; 22 mod
  Patch: https://git.openjdk.org/babylon/pull/268.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/268/head:pull/268

PR: https://git.openjdk.org/babylon/pull/268