Third try to fix access. Followup 6879efc2

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=12532
Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=922303

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=12532
Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=922303

Better fix for 480406cd
This way we behave the same on 32bit and 64bit archs.

Rewrote struct FDSelect3_4.ranges as ArrayOf
Updated FDSelect3_4::sanitize () to call ranges.sanitize ()
nRanges now a function to return a reference to ranges.len

Fixes https://github.com/harfbuzz/harfbuzz/issues/1308

Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=917031

Fixes https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=12312

Fixes https://bugs.chromium.org/p/chromium/issues/detail?id=918340

There are things can be improved on clang-format side I guess before
the full assertion, but is the best we can get for now I guess.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1536

As VSCode and Atom https://github.com/Microsoft/vscode/issues/44438 don't support it

oss-fuzz issue 12310

Catch missing imports and errors like #1520 and #1521

__E901,E999,F821,F822,F823__ are the "_showstopper_" [flake8](http://flake8.pycqa.org) issues that can halt the runtime with a SyntaxError, NameError, etc. Most other flake8 issues are merely "style violations" -- useful for readability but they do not effect runtime safety.
* F821: undefined name `name`
* F822: undefined name `name` in `__all__`
* F823: local variable name referenced before assignment
* E901: SyntaxError or IndentationError
* E999: SyntaxError -- failed to compile a file into an Abstract Syntax Tree

[skip ci]

In Python 3, __reload()__ was moved and __sys.setdefaultencoding()__ because the default is already utf-8.  Also __Error()__ is an _undefined name_ and __Exception()__ creates a generic exception.

Was good idea, but with C++ types with constructor/destructor, was getting in
the way as compiler was destructing those items where it was not desired.
Since C++ does not allow zero-sized arrays, just remove it...

I'm thinking about dropping it to zero, but that needs slight code changes.