tests: Fix compiler tests (#1678)

- This change updates syntax of constructors of Template Classes from
`class<T>()` to `class()`

- Initializes coherence to 0 in `src/mem/cache_blk.hh`

The above changes are made to solve the errors when compiling gem5 in
gcc 14

src/arch/arm/faults.hh

@@ -264,7 +264,7 @@ class ArmFaultVals : public ArmFault
     static FaultVals vals;
 
   public:
-    ArmFaultVals<T>(ExtMachInst mach_inst = 0, uint32_t _iss = 0) :
+    ArmFaultVals(ExtMachInst mach_inst = 0, uint32_t _iss = 0) :
         ArmFault(mach_inst, _iss) {}
     FaultName name() const override { return vals.name; }
     FaultOffset offset(ThreadContext *tc) override;

src/base/stats/units.hh

@@ -350,9 +350,9 @@ class Rate : public Base
         "otherwise, it would be a Ratio");
 
   private:
-    Rate<T1,T2>() {}
+    Rate() {}
   public:
-    Rate<T1,T2>(Rate<T1,T2> const&) = delete;
+    Rate(Rate const&) = delete;
     void operator=(Rate<T1,T2> const&) = delete;
     static Rate<T1,T2>*
     get()

src/dev/virtio/base.hh

@@ -477,7 +477,7 @@ class VirtQueue : public Serializable
             Index index;
         };
 
-        VirtRing<T>(PortProxy &proxy, ByteOrder bo, uint16_t size) :
+        VirtRing(PortProxy &proxy, ByteOrder bo, uint16_t size) :
             header{0, 0}, ring(size), _proxy(proxy), _base(0), byteOrder(bo)
         {}
 
@@ -550,7 +550,7 @@ class VirtQueue : public Serializable
 
       private:
         // Remove default constructor
-        VirtRing<T>();
+        VirtRing();
 
         /** Guest physical memory proxy */
         PortProxy &_proxy;

src/mem/cache/cache_blk.hh

@@ -461,7 +461,7 @@ class CacheBlk : public TaggedEntry
 
   protected:
     /** The current coherence status of this block. @sa CoherenceBits */
-    unsigned coherence;
+    unsigned coherence = 0;
 
     // The following setters have been marked as protected because their
     // respective variables should only be modified at 2 moments: