retrieve the value of the environment variable ERL_COMPILER_OPTIONS
in the same manner as used by file/2, forms/2 and output_generated/2

* bjorn/compiler/misc:
  misc_SUITE: Cover the remaining lines in beam_peep
  Avoid the dreaded "no_file" in warnings
  Eliminate crash for map updates in guards
  beam_block: Eliminate crash in beam_utils

* jv/compiler/mapsify-rec_env/PR-1082/OTP-13646:
  Convert dict() to map() in rec_env.erl

Add more filename/line number annotations while translating to
Core Erlang in v3_core, and ensure that sys_core_fold retains
existing annotations. The goal is to avoid that sys_core_fold
generate warnings with "no_file" instead of a filename.

beam_validator would complain that x(1) is uninitialized
in a test_heap instruction when attempting to compile
the following code with sys_core_fold turned off:

  foo(M) when not (M#{true := 0}); [M] ->
    ok.

Simplified, the generated BEAM assembly code looked like
this:

    test is_map BadMap x(0)
    put_map_exact Fail x(0) => x(1) ...
    jump BooleanStuff

  BadMap:
    move ok => x(1)
    jump Fail

  BooleanStuff:
    ...
    move Boolean => x(2)
    jump Build

  Fail:
    move false => x(2)

  Build:
    test_heap 2 3  %% x(0), x(1), x(2) must be live.
    ...

That is, if put_map_exact failed, control would transfer
to the label Fail without initializing x(1).

Fix that by making sure that x(1) is initilized even if
put_map_exact fails:

    test is_map BadMap x(0)
    put_map_exact BadLbl x(0) => x(1) ...
    jump OkLbl

  BadLbl:
    move ok => x(1)
    jump Fail

  OkLbl:
    jump BooleanStuff

  BadMap:
    move ok => x(1)
    jump Fail

  BooleanStuff:
    ...
    move Boolean => x(2)
    jump Build

  Fail:
    move false => x(2)

  Build:
    test_heap 2 3  %% x(0), x(1), x(2) must be live.
    ...

Note that this situation is rare, and that other optimization passes
(beam_dead and beam_jump in particular) will clean up this mess.

Somewhat simplified, beam_block would rewrite the target for
the first instruction in this code sequence:

    move x(0) => y(1)
    gc_bif '+' 1 x(0) => y(0)
    move y(1) => x(1)
    move nil => x(0)
    call 2 local_function/2

The resulting code would be:

    move x(0) => x(1)           %% Changed target.
    gc_bif '+' 1 x(0) => y(0)
    move x(1) => y(1)           %% Operands swapped (see 02d6135813).
    move nil => x(0)
    call 2 local_function/2

The resulting code is not safe because the x(1) will be killed
by the gc_bif instruction.

7a47b20c3a cleaned up move optimizations and would reject the
optimization if the target was an X register and an allocating
instruction was found. To avoid this bug, the optimization must be
rejected even if the target is a Y register.

We want to find bugs in the compiler during compilation. Validation of
match contexts was weak, which could allow serious bugs in the
generated code to slip through.

Using a record will make it much easier to add additional information.

* bjorn/compiler/misc:
  Eliminate unsafe use of Y registers
  beam_validator: Add is_bitstring/1 as a safe BIF
  beam_validator: Remove uncovered line
  Teach beam_utils:is_pure_test/1 to handle is_bitstr and is_function2
  beam_utils: Simplify handling of 'return' to eliminate uncovered line
  beam_jump: Clean up handling of labels before func_info
  beam_expect: Correctly handle blocks with multiple allocs
  v3_codegen: Don't confuse beam_validator
  v3_codegen: Correct code generation for an error/1 call in a guard
  beam_receive: Don't crash when encountering nonsensical code