Request for reviews (L): 6827605 and 6875866 for HS17

[Vladimir Kozlov]

http://cr.openjdk.java.net/~kvn/6827605/webrev.01

Fixed 6827605: new String intrinsics may prevent EA scalar replacement
Fixed 6875866: Intrinsic for String.indexOf() is broken on x86 with SSE4.2

Problem:
New String.indexOf SSE4.2 intrinsic prevents EA scalar replacement
of String object clone in the famous hot jbb code in Orderline.process:
stockData.indexOf("ORIGINAL").
Also String.indexOf SSE4.2 code starts string rescanning from
a wrong place after failing to match a part of substring.

Solution:
Modify String intrinsic methods to pass char[] pointers and
counters instead of string oops to allow EA eliminate
non-escaping string objects. Move some checks from
mach nodes encoding into ideal graph.
Add memory edge to AryEqNode.
Move common assembler code into MacroAssembler.
Fix 6875866.

Reviewed by:

Fix verified (y/n): y, refworkload

Other testing:
JPRT, CTW