Include rack-mini-profiler by default

I've used many development related performance tools, but the single most consistently helpful tool is `rack-mini-profiler`. 


The tool provides a lightweight UI element for each page, that shows the server response time. When clicked it expands to show more detail:

![](https://www.dropbox.com/s/0aciw4mk8c059n0/Screenshot%202017-07-24%2010.24.24.png?dl=1)


This can be used to detect expensive queries, N+1 issues and general performance related problems.

This also reverts the change to enable prepared statements by default on
MySQL (though I suspect we could enable them and it'd be great). This
change brings back a collector closer to the old `Bind` collector in
Arel. However, this one lives in AR, since this is an AR specific need.
Additionally, we only use it for statement caching, since the new
substitute collector in Arel is higher performance for most cases.

Honestly I don't think the tests that are fixed by this change should
have been merged. Passing a range or an array to `where` has a special
meaning. We need to solve the problem more concretely without overriding
the behavior that is present for *every* other type.

However, the damage has been done. These changes were in 5.1, so we need
a deprecation cycle to remove it.

Remove duplicated assertion in `test_count_with_join`

There's an actual bug in 213796fb around
prepared statements being disabled. I'm looking into it, but in the mean
time this gets the build green so it doesn't block other PRs

A common source of bugs and code bloat within Active Record has been the
need for us to maintain the list of bind values separately from the AST
they're associated with. This makes any sort of AST manipulation
incredibly difficult, as any time we want to potentially insert or
remove an AST node, we need to traverse the entire tree to find where
the associated bind parameters are.

With this change, the bind parameters now live on the AST directly.
Active Record does not need to know or care about them until the final
AST traversal for SQL construction. Rather than returning just the SQL,
the Arel collector will now return both the SQL and the bind parameters.
At this point the connection adapter will have all the values that it
had before.

A bit of this code is janky and something I'd like to refactor later. In
particular, I don't like how we're handling associations in the
predicate builder, the special casing of `StatementCache::Substitute` in
`QueryAttribute`, or generally how we're handling bind value replacement
in the statement cache when prepared statements are disabled.

This also mostly reverts #26378, as it moved all the code into a
location that I wanted to delete.

/cc @metaskills @yahonda, this change will affect the adapters

Fixes #29766.
Fixes #29804.
Fixes #26541.
Close #28539.
Close #24769.
Close #26468.
Close #26202.

There are probably other issues/PRs that can be closed because of this
commit, but that's all I could find on the first few pages.

Avoid modifying frozen string in check_schema_file

Fix test failure in message verifier tests

Add tests to MessageVerifier

Without this, I get the following result on my machine

```
# Running:

F

Failure:
MessageVerifierTest#test_backward_compatibility_messages_signed_without_metadata [/home/deivid/Code/rails/activesupport/test/message_verifier_test.rb:91]:
--- expected
+++ actual
@@ -1 +1 @@
-{:some=>"data", :now=>2010-01-01 00:00:00 +0100}
+{:some=>"data", :now=>2010-01-01 00:00:00 +0000}

bin/test test/message_verifier_test.rb:89
```

The paragraphs retread ground covered by the title and the usage examples,
so let's just remove them.

[ Assain Jaleel & Kasper Timm Hansen ]

Document metadata support for MessageEncryptor

[ci skip]

[ci skip]

Remove time stubs after each test

The queries both `res2` and `res3` are completely the same.
And also, `assert_nothing_raised` is covered by following assertion.

Use frozen string literal in actioncable/

Make actionview ready for frozen strings

Make actioncable ready for frozen strings

This was missed when the frozen string literal pragma was added to this
file because the string is only modified when running in the context of
a full Rails app, which wasn't covered by the test suite.

Use frozen string literal in actionmailer/

Fix a failued AR test when using OracleAdapter

[ Assain Jaleel & Kasper Timm Hansen ]

[ Assain Jaleel & Kasper Timm Hansen ]

So releasing 5.1 and 5.0 together won't require manual copy
and paste.

Basically revises the release flow to:

* Update the version in RAILS_VERSION + rake changelog:header
* Run rake all:verify (click around in the booted app)
* If that checks out, run rake release.

Sort enabled adapter extensions in schema dump

Reverts 7abb6e00.

Use `TRUE` and `FALSE` boolean literals for MySQL

Use `ArgumentError` instead of own error class

Make `type_map` to private because it is only used in the connection adapter

Updates Rails upgrade guide on `ActionView::Helpers::RecordTagHelper`