Exception message mismatch on invalid symbol encoding

[nirvdrum]

While pairing with @st0012 on removing TruffleRuby exclusions from the IRB test suite, we ran into a case where TruffleRuby uses a slightly different exception message than MRI when constructing a symbol from an invalid key. While error messages aren't exactly stable, I think we should try to match MRI where we can do so without too much effort.

MRI 3.1.3:

> ruby -v -e ':"\xAE"'
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [arm64-darwin21]
ruby: invalid symbol in encoding UTF-8 :"\\xAE" (EncodingError)

> ruby -v -e '"\xAE".to_sym'
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [arm64-darwin21]
-e:1:in `to_sym': invalid symbol in encoding UTF-8 :"\\xAE" (EncodingError)
        from -e:1:in `<main>'

MRI 3.2.0:

ruby -v -e ':"\xAE"'
ruby 3.2.0 (2022-12-25 revision a528908271) [arm64-darwin21.5.0]
ruby: invalid symbol in encoding UTF-8 :"\xAE" (EncodingError)

> ruby -v -e '"\xAE".to_sym'
ruby 3.2.0 (2022-12-25 revision a528908271) [arm64-darwin21.5.0]
-e:1:in `to_sym': invalid symbol in encoding UTF-8 :"\xAE" (EncodingError)
        from -e:1:in `<main>'

TruffleRuby 23.0.0-dev:

> jt ruby -v -e ':"\xAE"'
truffleruby 23.0.0-dev-8bb04d8c, like ruby 3.1.3, GraalVM CE JVM [aarch64-darwin]
truffleruby: invalid encoding symbol (EncodingError)

> jt ruby -v -e '"\xAE".to_sym'
truffleruby 23.0.0-dev-8bb04d8c, like ruby 3.1.3, GraalVM CE JVM [aarch64-darwin]
<internal:core> core/string.rb:155:in `to_sym': invalid encoding symbol (EncodingError)
        from -e:1:in `<main>'

I've tried several versions of MRI going back to 2.7.5 and they all use the same message. If it's a historical divergence, it happened a while ago.

[andrykonchin]

Fixed in 145d23e