Also, this adds a test that guarantees that the ordering of several
push() calls in a row is always preserved in synchronous readable streams

There are cases where a push() call would return true, even though
the thing being pushed was in fact way way larger than the high
water mark, simply because the 'needReadable' was already set, and
would not get unset until nextTick.

In some cases, this could lead to an infinite loop of pushing data
into the buffer, never getting to the 'readable' event which would
unset the needReadable flag.

Fix by splitting up the emitReadable function, so that it always
sets the flag on this tick, even if it defers until nextTick to
actually emit the event.

Also, if we're not ending or already in the process of reading, it
now calls read(0) if we're below the high water mark.  Thus, the
highWaterMark value is the intended amount to buffer up to, and it
is smarter about hitting the target.

It seems like a good idea on the face of it, but lowWaterMarks are
actually not useful, and in practice should always be set to zero.

It would be worthwhile for writers if we actually did some kind of
writev() type of thing, but actually this just delays calling write()
and the overhead of doing a bunch of Buffer copies is not worth the
slight benefit of calling write() fewer times.

lib/path.js:
  - throws a TypeError on the filter if the argument is not a string.

test/simple/test-path.js:
  - removed the test to check if non-string types are filtered.
  - added a test to check if path.join throws TypeError on arguments that
    are not strings.

lib/http.js is using stream._handle.readStart/readStop to control
data-flow coming out from underlying stream. If this methods are not
present - data might be buffered regardless of whether it'll be read.

see #4657

Apperently there is a case where calling the spinner was required after
passing a callback to nextTick(). This fixes that issue.

Fix #4795

It's a buffer so it's never bigger than Buffer::kMaxLength bytes,
which in turn is always < INT_MAX.

Checks have been simplified and optimized for most-used cases.

Calling Buffer with another Buffer as the subject will now use the
SlowBuffer Copy method instead of the for loop.

No need to call for value coercion, just place the ternary inline.

It's not used outside of src/node.cc so make it static.

ASN1_STRING_to_UTF8() passes an ASN1_STRING to ASN1_STRING_set() but forgot to
initialize the `length` field.

Fixes the following valgrind error:

  $ valgrind -q --track-origins=yes --num-callers=19 \
      out/Debug/node test/simple/test-tls-client-abort.js
  ==2690== Conditional jump or move depends on uninitialised value(s)
  ==2690==    at 0x784B69: ASN1_STRING_set (asn1_lib.c:382)
  ==2690==    by 0x809564: ASN1_mbstring_ncopy (a_mbstr.c:204)
  ==2690==    by 0x8090F0: ASN1_mbstring_copy (a_mbstr.c:86)
  ==2690==    by 0x782F1F: ASN1_STRING_to_UTF8 (a_strex.c:570)
  ==2690==    by 0x78F090: asn1_string_canon (x_name.c:409)
  ==2690==    by 0x78EF17: x509_name_canon (x_name.c:354)
  ==2690==    by 0x78EA7D: x509_name_ex_d2i (x_name.c:210)
  ==2690==    by 0x788058: ASN1_item_ex_d2i (tasn_dec.c:239)
  ==2690==    by 0x7890D4: asn1_template_noexp_d2i (tasn_dec.c:746)
  ==2690==    by 0x788CB6: asn1_template_ex_d2i (tasn_dec.c:607)
  ==2690==    by 0x78877A: ASN1_item_ex_d2i (tasn_dec.c:448)
  ==2690==    by 0x7890D4: asn1_template_noexp_d2i (tasn_dec.c:746)
  ==2690==    by 0x788CB6: asn1_template_ex_d2i (tasn_dec.c:607)
  ==2690==    by 0x78877A: ASN1_item_ex_d2i (tasn_dec.c:448)
  ==2690==    by 0x787C93: ASN1_item_d2i (tasn_dec.c:136)
  ==2690==    by 0x78F5E4: d2i_X509 (x_x509.c:141)
  ==2690==    by 0x7C9B91: PEM_ASN1_read_bio (pem_oth.c:81)
  ==2690==    by 0x7CA506: PEM_read_bio_X509 (pem_x509.c:67)
  ==2690==    by 0x703C9A: node::crypto::SecureContext::AddRootCerts(v8::Arguments const&) (node_crypto.cc:497)
  ==2690==  Uninitialised value was created by a stack allocation
  ==2690==    at 0x782E89: ASN1_STRING_to_UTF8 (a_strex.c:560)

When perlasm generates MASM code it sets the assembler target to 468.
In this mode MASM refuses to assemble a couple of instructions. Bumping
the target to 686 solves this problem.

It used to be off before. It's extremely unlikely that such an attack
would be a viable attack against node. And it makes AES much slower.

For throughput benchmarks, run with just 5s durations rather than 1s and 3s.

For startup benchmark, run with just a single 1s duration, since it's very
consistent anyway.

Remove ab, since it's no longer used.

Also, make it work properly with current node.

Better covered by the other benchmark/fs scripts.