This reverts commit e4e74c27.

See https://github.com/harfbuzz/harfbuzz/issues/1829

Now is flaky let's just increase and maybe investigate later

And enable more tests able to trig the issue.

This reverts commit 62e60322 since it
breaks building HarfBuzz as part of Chromium.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1821.

Yoohoo.  This seems to be precise enough!  Let's see if it sticks.
I'm asking Dominik to run this in Chrome test suite and report.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1801

Part of https://github.com/harfbuzz/harfbuzz/issues/1801

Part of https://github.com/harfbuzz/harfbuzz/issues/1801

The assumption that compiler optimizes "upem/2" to a shift only
works if upem is unsigned...  Anyway, spoon-feed the compiler.

Fixes https://github.com/harfbuzz/harfbuzz/issues/1818

Just for those that are normally built into libharfbuzz itself.

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

This reverts commit c4aa10eb.

Broke several compilers... Sigh.  The version without constexpr
didn't fully optimize out the unreachable code on clang.
So, revert it is...

Being conservative.  Also not sure it makes any real difference
in our codebase.

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

This actually makes it build now!

Part https://github.com/harfbuzz/harfbuzz/issues/1809

Keeping open to add tests, CI, etc.

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

This was non-standard, and unused anyway.

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

Part of https://github.com/harfbuzz/harfbuzz/issues/1809

Make harfbuzz working on all existing versions of Windows

I tried to cross compile harfbuzz for Windows and an error was generated because `DWrite_1.h` was not found.
This happened because the filesystem is case sensitive and for this reason that include file was not found.
The right name of the file to be used is `dwrite_1.h`, with all letters not capitalized:
https://docs.microsoft.com/en-us/windows/desktop/api/dwrite_1/
I also verified in the installation of VS2017 with Windows Kit v10 and in that place it was also lower case.
So, in my opinion it should be better to change this.

Not used anymore since DWRITE is loaded dynamically.

Also checks if DWriteCreateFactory() has been executed successfully.