Also known as “everyone is suddenly trying to use HTML5 export for the jam”

Fixes

• Fixed GMLive producing invalid JS on HTML5 due to static a=[] syntax (report #186114).
  This is a re-run of a 2.3.0 bug (#177719), which suggests that my report didn’t make it into unit tests.
• Fixed a startup error due to gc_target_frame_time and gc_get_target_frame_time missing in the HTML5 runtime despite being in fnames list.
• Fixed some functions not working due to variable_struct_* functions mis-firing for id (and other built-in) variables (report #186192).
• Fixed postfix ++/– operators not working for some of the data structure accessors.
• Fixed repeat (0.66) executing one iteration unlike 0 iterations in base GML.

Misc.

• live_method_get_self doesn’t work on HTML5 because method_get_self doesn’t work on HTML5 for non-instances (report #186111)
• I have added a script that references a handful of functions/variables so that GMS2 IDE doesn’t complain about them being “unused”.