C#: Add nomagic pragmas to fix performance issues

Author: tamasvajk

csharp/ql/src/semmle/code/csharp/Variable.qll

@@ -237,6 +237,7 @@ class Parameter extends DotNet::Parameter, LocalScopeVariable, Attributable, Top
    * The assigned arguments to `x` are `1` and `4`, the assigned argument to
    * `y` is `5`, and the assigned arguments to `z` are `3` and `6`, respectively.
    */
+  pragma[nomagic]
   Expr getAnAssignedArgument() { result = getCallable().getACall().getArgumentForParameter(this) }
 
   /** Holds if this parameter is potentially overwritten in the body of its callable. */

csharp/ql/src/semmle/code/csharp/commons/StructuralComparison.qll

@@ -77,7 +77,7 @@ abstract class StructuralComparisonConfiguration extends string {
 
   private predicate sameByValue(Expr x, Expr y) { sameByValueAux(x, y, y.getValue()) }
 
-  pragma[noinline]
+  pragma[nomagic]
   private predicate sameByValueAux(Expr x, Expr y, string value) {
     candidateInternal(x, y) and
     value = x.getValue()

csharp/ql/src/semmle/code/csharp/controlflow/Guards.qll

@@ -1248,6 +1248,7 @@ module Internal {
       )
     }
 
+    pragma[nomagic]
     private Expr getAnEqualityCheckVal(Expr e, AbstractValue v, AbstractValue vExpr) {
       result = getAnEqualityCheck(e, v, vExpr.getAnExpr())
     }