Add missing decoding patterns toRoundUpToInstrBoundary

Summary:
The RoundUpToInstrBoundary determines intructions boundary and it's used to determine how to patch (intercept) functions.

The current x64-bit implementation is incomplete. This patch is adding patterns observed when trying to sanitize a 64-bit executable on my computer.

Thw two current functions not intercepted are:
```
RaiseExceptionStub:
000000007720C3B0 EB 06                jmp         RaiseException (07720C3B8h)  
000000007720C3B2 90                   nop  
000000007720C3B3 90                   nop  
000000007720C3B4 90                   nop  
000000007720C3B5 90                   nop  
000000007720C3B6 90                   nop  
000000007720C3B7 90                   nop  
RaiseException:
000000007720C3B8 FF 25 3A 18 09 00    jmp         qword ptr [__imp_RaiseException (07729DBF8h)]  
000000007720C3BE 8B 44 24 54          mov         eax,dword ptr [rsp+54h]  
000000007720C3C2 85 C0                test        eax,eax  
000000007720C3C4 0F 84 F5 05 00 00    je          Wow64NtCreateKey+12Fh (07720C9BFh)  
```

```
CreateThreadStub:
0000000077215A10 48 83 EC 48          sub         rsp,48h  
0000000077215A14 48 8B 44 24 78       mov         rax,qword ptr [rsp+78h]  
0000000077215A19 48 89 44 24 38       mov         qword ptr [rsp+38h],rax  
0000000077215A1E 8B 44 24 70          mov         eax,dword ptr [rsp+70h]  
```

Reviewers: rnk

Subscribers: wang0109, chrisha

Differential Revision: http://reviews.llvm.org/D21519

llvm-svn: 273176