Remove legacy emdump tool (#24686)

This tool dates back to the asm.js days, and only known how to analyze
JS files. However its very out-of-date and doesn't seem to understand
commonly used things like arrow functions so doesn't give good results
on the JS files that emscripten generates today.

Since the JS code the emscripten generates these days is basically
normal JS (i.e. not asm.js) then other/existing static analysis tools
should work find rather than this one so I don't see any point in
maintaining this.

Author: sbc100

ChangeLog.md

@@ -20,6 +20,8 @@ See docs/process.md for more on how version tagging works.
 
 4.0.11 (in development)
 -----------------------
+- `emdump` tool/script was removed.  This tool was mostly useful for analyzing
+  asm.js code, which emscripten has not generated in a long time now.
 - Add support for [Source-based Code Coverage](https://clang.llvm.org/docs/SourceBasedCodeCoverage.html)
   To build with coverage enabled use `-fprofile-instr-generate -fcoverage-mapping`. (#24160)
 - The `ENVIRONMENT` setting will now be automatically updated to include