Simplify/Refactor exception handling and last statement value

[HalidOdat]

This PR simplifies some vm/bytecompiler logic which should make it easier to implement optimizations (since the optimizer has to account for all this complexity).

It changes the following:

• Remove opcodes PopIfThrown, PopOnReturnAdd, PopOnReturnSub, CatchStart, CatchEnd and CatchEnd2, BreakLabel
• Add SetReturnValue and GetReturnValue opcodes (return value is currently stored on the call frame, which is not optimal will change that once we refactor function calling in the vm).
• Remove loop value in EnvEntry
• Only generate Last statement use_expr if needed.
• Add fp (frame pointer) to try EnvEntry to truncate the stack instead of pop_on_return on call frame (which was removed).
• Remove loop value logic from break and continue opcodes

[github-actions]

Test262 conformance changes

Test result	main count	PR count	difference
Total	94,842	94,842	0
Passed	74,663	74,663	0
Ignored	18,812	18,812	0
Failed	1,367	1,367	0
Panics	0	0	0
Conformance	78.72%	78.72%	0.00%

[codecov]

Codecov Report

Merging #3053 (bcb7631) into main (7026c71) will decrease coverage by 0.16%.
The diff coverage is 90.22%.

❗ Current head bcb7631 differs from pull request most recent head fed05d7. Consider uploading reports for the commit fed05d7 to get more accurate results

@@            Coverage Diff             @@
##             main    #3053      +/-   ##
==========================================
- Coverage   50.55%   50.39%   -0.16%     
==========================================
  Files         446      445       -1     
  Lines       46071    45909     -162     
==========================================
- Hits        23292    23138     -154     
+ Misses      22779    22771       -8     

Impacted Files	Coverage Δ
boa_engine/src/bytecompiler/expression/mod.rs	56.71% <0.00%> (-0.22%)	⬇️
boa_engine/src/bytecompiler/function.rs	90.62% <ø> (-0.15%)	⬇️
boa_engine/src/bytecompiler/statement/continue.rs	38.80% <ø> (+2.69%)	⬆️
boa_engine/src/vm/code_block.rs	61.00% <ø> (ø)
boa_engine/src/vm/flowgraph/mod.rs	0.00% <0.00%> (ø)
boa_engine/src/vm/opcode/generator/mod.rs	11.36% <0.00%> (-0.14%)	⬇️
boa_engine/src/vm/opcode/mod.rs	69.23% <ø> (ø)
boa_engine/src/vm/opcode/pop/mod.rs	100.00% <ø> (+5.00%)	⬆️
boa_engine/src/bytecompiler/class.rs	15.62% <25.00%> (+0.09%)	⬆️
boa_engine/src/bytecompiler/jump_control.rs	93.04% <83.87%> (-0.19%)	⬇️
... and 18 more

... and 4 files with indirect coverage changes

[jedel1043]

Really nice clean-up!

[raskad]

Great refactor!