ref #3492 #3515 #3517

So that `yield expr_with_error` will cause the error from the
argument rather than `LocalJumpError` when no block is given.

916b8e let code executed with mrb->exc set, and may cause a crash
like #3519. Instead modified OP_RESCUE again. To retrieve the exception
object, we use `OP_RESCUE R(A), 0, 0` (old behavior). To compare the
exception object and the class, we use `OP_RESCUE R(A), R(B), 1`.

The reason we use OP_RESCUE for two instruction switched by operand
C is to save the instruction space.

As a result, the following code:
```ruby
begin
  raise "a"
rescue TypeError
  p 1
rescue RuntimeError
  p 2
end
```
will be compiled as:
```
irep 0x55cd1f565cb0 nregs=4 nlocals=1 pools=1 syms=4 reps=0
file: -
    2 000 OP_ONERR	005
    2 001 OP_LOADSELF	R1
    2 002 OP_STRING	R2	L(0)	; "a"
    2 003 OP_SEND	R1	:raise	1
    2 004 OP_JMP	023
    2 005 OP_RESCUE	R1
    3 006 OP_GETCONST	R2	:TypeError
    3 007 OP_RESCUE	R1	R2	cont
    3 008 OP_JMPIF	R2	010
    3 009 OP_JMP	014
    4 010 OP_LOADSELF	R1
    4 011 OP_LOADI	R2	1
    4 012 OP_SEND	R1	:p	1
    4 013 OP_JMP	024
    5 014 OP_GETCONST	R2	:RuntimeError
    5 015 OP_RESCUE	R1	R2	cont
    5 016 OP_JMPIF	R2	018
    5 017 OP_JMP	022
    6 018 OP_LOADSELF	R1
    6 019 OP_LOADI	R2	2
    6 020 OP_SEND	R1	:p	1
    6 021 OP_JMP	024
    6 022 OP_RAISE	R1
    6 023 OP_POPERR	1
    6 024 OP_STOP
```

The old OP_RESCUE took one operand A, which specifies a class
to match with the exception. The new OP_RESCUE takes tree operands:

A: the register to hold exception
B: the matching exception; the match result will be stored here.
C: the continuation; if C is zero, the exception will be stored to R(A)
   otherwise, the value from R(A) is used as a exception.

Thus,
```ruby
begin
  raise "a"
rescue TypeError
  p 1
rescue RuntimeError
  p 2
end
```
will be compiled as
```
irep 0x557a06667aa0 nregs=4 nlocals=1 pools=1 syms=4 reps=0
file: /tmp/e.rb
2 000 OP_ONERR  005
2 001 OP_LOADSELF R1
2 002 OP_STRING R2  L(0)  ; "a"
2 003 OP_SEND R1  :raise  1
2 004 OP_JMP  022
3 005 OP_GETCONST R2  :TypeError
3 006 OP_RESCUE R1  R2
3 007 OP_JMPIF  R2  009
3 008 OP_JMP  013
4 009 OP_LOADSELF R1
4 010 OP_LOADI  R2  1
4 011 OP_SEND R1  :p  1
4 012 OP_JMP  023
5 013 OP_GETCONST R2 :RuntimeError
5 014 OP_RESCUE R1 R2  cont
5 015 OP_JMPIF  R2  017
5 016 OP_JMP  021
6 017 OP_LOADSELF R1
6 018 OP_LOADI  R2  2
6 019 OP_SEND R1  :p  1
6 020 OP_JMP  023
6 021 OP_RAISE  R1
6 022 OP_POPERR 1
6 023 OP_STOP
```

The new VM can accept old OP_RESCUE. The mruby compatible VM (namely
mruby/c) should be updated to support the new OP_RESCUE behavior.

The issue (and the fix) was reported by https://hackerone.com/dgaletic

http://hkdnet.hatenablog.com/entry/2017/02/06/080000 (Japanese)

This issue was first reported by https://hackerone.com/geeknik
The fix was proposed by @titanous

The fix was proposed by @titanous

Reported by Denis Kasak https://hackerone.com/dkasak

Also msym size changed to 512 from 256.

The issue is that when there are more than 126 arguments an array needs
to be created to pass the arguments on with.

Reported by https://hackerone.com/revskills

Reported by https://hackerone.com/haquaman

The function was renamed to `mrb_float_read(const char*, char**)`.