Bug 76494 - #!/usr/bin/python in testsuite

https://bugs.freedesktop.org/show_bug.cgi?id=76494

On ArchLinux, /usr/bin/python is linked to python 3 so
HarfBuzz `make check` is broken there.

This makes hb_test_tools.py compatible with python 3 while
no breaking it on python 2.

In Oriya, a ZWJ/ZWNJ might be added before candrabindu to encourage
or stop ligation of the candrabindu.  This is clearly specified in
the Unicode section on Oriya.  Allow it there.  Note that Uniscribe
doesn't allow this.

Micro tests added using Noto Sans Oriya draft.

No changes in numbers.  Currently at:

BENGALI: 353725 out of 354188 tests passed. 463 failed (0.130722%)
DEVANAGARI: 707307 out of 707394 tests passed. 87 failed (0.0122987%)
GUJARATI: 366349 out of 366457 tests passed. 108 failed (0.0294714%)
GURMUKHI: 60732 out of 60747 tests passed. 15 failed (0.0246926%)
KANNADA: 951190 out of 951913 tests passed. 723 failed (0.0759523%)
KHMER: 299070 out of 299124 tests passed. 54 failed (0.0180527%)
MALAYALAM: 1048147 out of 1048334 tests passed. 187 failed (0.0178378%)
ORIYA: 42320 out of 42329 tests passed. 9 failed (0.021262%)
SINHALA: 271662 out of 271847 tests passed. 185 failed (0.068053%)
TAMIL: 1091753 out of 1091754 tests passed. 1 failed (9.15957e-05%)
TELUGU: 970555 out of 970573 tests passed. 18 failed (0.00185457%)

Was broken in 615d00ea.

Fixes https://github.com/behdad/harfbuzz/pull/48

Micro-test added.

See comments.

Micro-test added.

Seems to be what Uniscribe does.

At this point I think it's work checking our default...

Fixes Bug 76767 - Zeroing of advance of 2nd component of multiple
substitution with SBL Hebrew
https://bugs.freedesktop.org/show_bug.cgi?id=76767

Micro-test added.

Looks like Unsicribe responds to the 'mymr' tag by zeroing marks
GDEF_LATE instead of generic-shaper UNICODE_LATE.  Implement that.

Fixes
Bug 81775 - Incorrect Rendering with harfbuzz-ng myanmar unicode
https://bugs.freedesktop.org/show_bug.cgi?id=81775

Micro-test added based on Padauk.

See comment.

Micro-tests added.

From
https://code.google.com/p/chromium/issues/detail?id=393896

Follows the order of the Arabic/Syriac specs.  Also don't stop
between rlig and calt in non-Arabic scripts.

Micro-tests for Arabic and Mongolian added for the latter.

This reverts bf029281 and fixes it properly.  That commit
was not enough as it was only inheriting the shaping_action
for prev_action, but not curr_action.

Micro-test added.

https://code.google.com/p/chromium/issues/detail?id=393896

Originally we fixed those in 79d1007a.
However, fonts like MongolianWhite don't have GDEF, but have IgnoreMarks
in their LigatureSubstitute init/etc features.  We were synthesizing a
GDEF class of mark for Mongolian Variation Selectors and as such the
ligature lookups where not matching.  Uniscribe doesn't do that.

I tried with more sophisticated fixes, like, if there is no GDEF and
a lookup-flag mismatch happens, instead of rejecting a match, try
skipping that glyph.  That surely produces some interesting behavior,
but since we don't want to support fonts missing GDEF more than we have
to, I went for this simpler fix which is to always mark
default-ignorables as base when synthesizing GDEF.

Micro-test added.

Fixes rest of https://bugs.freedesktop.org/show_bug.cgi?id=65258

Apparently on travis-ci, bash is linked to dash, which doesn't
understand "let".  Failing tests were not being noticed.  See eg:

  https://travis-ci.org/behdad/harfbuzz/jobs/29544211

Don't rely on bash.

If pre-base reordering Ra is NOT formed (or formed and then
broken up), we should consider that Ra as base.  This is
observable when there's a left matra or dotreph that positions
before base.

Now, it might be that we shouldn't do this if the Ra happend
to form a below form.  We can't quite deduce that right now...

Micro test added.  Also at:

https://code.google.com/a/google.com/p/noto-alpha/issues/detail?id=186#c29

Normally if you want to, say, conditionally prevent a 'pref', you
would use blocking contextual matching.  Some designers instead
form the 'pref' form, then undo it in context.  To detect that
we now also remember glyphs that went through MultipleSubst.

In the only place that this is used, Uniscribe seems to only care
about the "last" transformation between Ligature and Multiple
substitions.  Ie. if you ligate, expand, and ligate again, it
moves the pref, but if you ligate and expand it doesn't.  That's
why we clear the MULTIPLIED bit when setting LIGATED.

Micro-test added.  Test: U+0D2F,0D4D,0D30 with font from:

[1]
https://code.google.com/a/google.com/p/noto-alpha/issues/detail?id=186#c29

Tests: U+0967,0951 U+0031,093F

Only allow it on DOTTED CIRCLE.  No effect on test numbers.

Test: U+0930,094D,00A0

One of them currently produces dotted-circle.  Fix and detailed
message coming.

Currently fails.

Work around broken automake-1.13 changes.

Fix tests build.

https://bugs.freedesktop.org/show_bug.cgi?id=71353

All three are broken right now according to Roozbeh.

https://bugs.freedesktop.org/show_bug.cgi?id=71947
https://bugs.freedesktop.org/show_bug.cgi?id=71948
https://bugs.freedesktop.org/show_bug.cgi?id=71949

Bug 70509 - Candrabindu+Visarga doesn't work in Devanagari
https://bugs.freedesktop.org/show_bug.cgi?id=70509

We categorize both bindus and visarga as syllable-modifiers.
OT spec doesn't actually say what characters go in the syllable
modifier category, and allows one.  We just allow up to two now.

Test case: U+0930,U+0941,U+0901,U+0903

Uniscribe currently doesn't support that and produces a
dotted circle.

Rachana-0.6 implements dot-reph by ligation, so we shouldn't move it.
Uniscribe doesn't either.  Test case:

  U+0D4E,U+0D1A,U+0D4D,U+0D1A,U+0D4D