Remove mentions of Itanium (#4597)

* Remove mentions of Itanium

Author: svick

xml/System.Threading/Interlocked.xml

@@ -1985,8 +1985,6 @@ If `comparand` and the object in `location1` are equal by reference, then `value
 ## Remarks  
  This method was added to the <xref:System.Threading.Interlocked> class in the [!INCLUDE[net_v45](~/includes/net-v45-md.md)] as a convenience; it's a wrapper for the <xref:System.Threading.Thread.MemoryBarrier%2A?displayProperty=nameWithType> method.  
   
- <xref:System.Threading.Interlocked.MemoryBarrier%2A> is required only on multiprocessor systems that have weak memory ordering (for example, a system that employs multiple Intel Itanium processors).  
-  
  For most purposes, the C# `lock` statement, the Visual Basic `SyncLock` statement, or the <xref:System.Threading.Monitor> class provide easier ways to synchronize data.  
   
  ]]></format>

xml/System.Threading/Thread.xml

@@ -2779,8 +2779,6 @@ The value is not guaranteed to be a zero-based processor number.
           <format type="text/markdown"><![CDATA[  
   
 ## Remarks  
- <xref:System.Threading.Thread.MemoryBarrier%2A> is required only on multiprocessor systems with weak memory ordering (for example, a system employing multiple Intel Itanium processors).  
-  
  For most purposes, the C# `lock` statement, the Visual Basic `SyncLock` statement, or the <xref:System.Threading.Monitor> class provide easier ways to synchronize data.  
   
  ]]></format>

xml/System/String.xml

@@ -720,7 +720,7 @@ Examples of instantiating strings:
 
      The array must contain Unicode characters. In C++, this means that the character array must be defined either as the managed <xref:System.Char>[] type or the unmanaged`wchar_t`[] type.
 
-     If the <xref:System.String.%23ctor%28System.Char%2A%29> overload is called and the array is not null-terminated, or if the <xref:System.String.%23ctor%28System.Char%2A%2CSystem.Int32%2CSystem.Int32%29> overload is called and `startIndex` + `length`-1 includes a range that it outside the memory allocated for the sequence of characters, the behavior of the constructor is system-dependent, and an access violation may occur. In addition, on the Intel Itanium processor, calls to the <xref:System.String.%23ctor%28System.Char%2A%2CSystem.Int32%2CSystem.Int32%29> constructor may throw a <xref:System.DataMisalignedException> exception. If this occurs, call the <xref:System.String.%23ctor%28System.Char%5B%5D%2CSystem.Int32%2CSystem.Int32%29> instead.
+     If the <xref:System.String.%23ctor%28System.Char%2A%29> overload is called and the array is not null-terminated, or if the <xref:System.String.%23ctor%28System.Char%2A%2CSystem.Int32%2CSystem.Int32%29> overload is called and `startIndex` + `length`-1 includes a range that is outside the memory allocated for the sequence of characters, the behavior of the constructor is system-dependent, and an access violation may occur.
 
 -   From a pointer to a signed byte array. Either the entire array or a specified range can be used to initialize the string. The sequence of bytes can be interpreted by using the default code page encoding, or an encoding can be specified in the constructor call. If the constructor tries to instantiate a string from an entire array that is not null-terminated, or if the range of the array from `value` + `startIndex` to `value` + `startIndex` + `length` -1 is outside of the memory allocated for the array, the behavior of this constructor is system-dependent, and an access violation may occur.