Add support for TLS_FALLBACK_SCSV

Backport of commits:

external/conscrypt: 8d7e23e117da591a8d48e6bcda9ed6f58ff1a375
libcore: e6a6e935
libcore: 957ec8b0

Plus additional changes to:
luni/src/main/java/org/apache/harmony/xnet/provider/jsse/OpenSSLServerSocketImpl.java
luni/src/main/java/org/apache/harmony/xnet/provider/jsse/OpenSSLSocketImpl.java
luni/src/test/java/libcore/java/net/URLConnectionTest.java
luni/src/test/java/org/apache/harmony/xnet/provider/jsse/CipherSuiteTest.java
support/src/test/java/libcore/java/security/StandardNames.java

to account for KitKat differences.

Bug: 17750026
Change-Id: Ic6e9474275bc3ffec3b5c2d6df1f8d6ffe77bff8