Fixed a syntax mistake regarding blocks in specs.

The block wasn't passed to `raise_error`, due to missing parenthesis
around it and the block.
Adding them would've looked a bit awkward, so I put the second
expectation in a lambda and passed it as a block to `raise_error`.
Add specs on Module#const_get raising a NameError with missing constant.

NameError should be raised with the missing constant as the second
argument, so it would show up when calling `#name` on the error.
Module#const_get: raise NameError with missing constant name.
Add spec for Dir::Glob not recursing into symlinks
Use File::Stat.lstat in Dir::Glob to avoid recursing into symlinks
Merge pull request #2481 from leocassarani/dir-glob-symlinks

Don't follow symlinks when using Dir::Glob with recursive directories
Improve clone error message for immediates

Fixes #2486
Improve exception message for built in allocation disabled
Add specs for String#clone
Add specs for modifying dupped and cloned strings

This uses [] to make sure we slice the string and get a (if implemented)
unshared string back.
Add custom String#clone for managed shared state properly

Strings can share the underlying byte array. This makes sure we mark the
clone as shared.

Fixes #2485
Fix timeout issue

This would add requests already finished that would cause spurious
interrupts later on causing issues.
Add spec for issue#1614.
Fix issue#1614.
Move part of code into fixtures/precedence.rb. Shorten description of
spec.
Improve JIT debugging when setup fails
Add specs for Array#values_at with weird Range

* https://github.com/rubinius/rubinius/pull/2490#pullrequestreviewcomment-5347303
* https://github.com/rubinius/rubinius/pull/2490#pullrequestreviewcomment-5347339
Fix Array#values_at with weird Range for 2.0
Improve description of spec for issue#1614
Merge pull request #2489 from darkgrin/issue1614

Fix for issue#1614