[asan] Fix interception unittest on Windows64.

[wang0109]

Summary

mov edi,edi is _not_ NOP in 64-bit, use 66,90h instead.
This bug was causing interception unittest to crash on Windows64.

Credits to etienneb for finding the root cause.

[etienneb]

lgtm

[rnk]

lgtm

compiler-rt/trunk/lib/interception/interception_win.cc

switch (*(u16*)address) {
     case 0x5440:  // push rsp
     case 0x5540:  // push rbp
     case 0x5640:  // push rsi
     case 0x5740:  // push rdi
     case 0x5441:  // push r12
     case 0x5541:  // push r13
     case 0x5641:  // push r14
     case 0x5741:  // push r15
+    case 0x9066:  // Two-byte NOP
       return 2;
   }
 
   switch (0x00FFFFFF & *(u32*)address) {
     case 0xe58948:    // 48 8b c4 : mov rbp, rsp
     case 0xc18b48:    // 48 8b c1 : mov rax, rcx
     case 0xc48b48:    // 48 8b c4 : mov rax, rsp
     case 0xd9f748:    // 48 f7 d9 : neg rcx

compiler-rt/trunk/lib/interception/tests/interception_win_test.cc

static void LoadActiveCode(
   for (size_t i = 0; i < padding; ++i)
     ActiveCode[position++] = 0x90;
 
   // Keep track of the entry point.
   *entry_point = (uptr)&ActiveCode[position];
 
   // Add the detour instruction (i.e. mov edi, edi)
   if (prefix_kind == FunctionPrefixDetour) {
+#if SANITIZER_WINDOWS64
+    // Note that "mov edi,edi" is NOP in 32-bit only, in 64-bit it clears
+    // higher bits of RDI.
+    // Use 66,90H as NOP for Windows64.
+    ActiveCode[position++] = 0x66;
+    ActiveCode[position++] = 0x90;
+#else
+    // mov edi,edi.
     ActiveCode[position++] = 0x8B;
     ActiveCode[position++] = 0xFF;
+#endif
+
   }
 
   // Copy the function body.
   for (size_t i = 0; i < sizeof(T); ++i)
     ActiveCode[position++] = code[i];
 }
 
 int InterceptorFunctionCalled;