Fix IL interpreter build on GCC.

[heiher]

Build Command:

./build.sh clr -c debug -gcc -cmakeargs "-DFEATURE_INTERPRETER=1"
./build.sh clr -c release -gcc -cmakeargs "-DFEATURE_INTERPRETER=1"

Errors:

  /home/heiher/git/dotnet/runtime/src/coreclr/src/vm/interpreter.h:1041:35: error: extra qualification ‘Interpreter::’ on member ‘MethodHandleToInterpreterMethInfoPtr’ [-fpermissive]
   1041 |     static InterpreterMethodInfo* Interpreter::MethodHandleToInterpreterMethInfoPtr(CORINFO_METHOD_HANDLE md);

  /home/heiher/git/dotnet/runtime/src/coreclr/src/vm/interpreter.cpp:4922:23: error: comparison of integer expressions of different signedness: ‘unsigned int’ and ‘int’ [-Werror=sign-compare]
   4922 |         else if (val2 == -1 && val1 == static_cast<T>(((UINT64)1) << (sizeof(T)*8 - 1))) // min int / -1 is not representable.
        |                  ~~~~~^~~~~

  /home/heiher/git/dotnet/runtime/src/coreclr/src/vm/interpreter.cpp: In static member function ‘static bool Interpreter::MethodMayHaveLoop(BYTE*, unsigned int)’:
  /home/heiher/git/dotnet/runtime/src/coreclr/src/inc/debugmacros.h:45:14: error: this statement may fall through [-Werror=implicit-fallthrough=]
     45 |              if (!(expr)) {                                                 \
        |              ^~
  /home/heiher/git/dotnet/runtime/src/coreclr/src/inc/debugmacros.h:54:26: note: in expansion of macro ‘_ASSERTE_MSG’
     54 |   #define _ASSERTE(expr) _ASSERTE_MSG(expr, #expr)
        |                          ^~~~~~~~~~~~
  /home/heiher/git/dotnet/runtime/src/coreclr/src/vm/interpreter.cpp:3538:13: note: in expansion of macro ‘_ASSERTE’
   3538 |             _ASSERTE(op < CEE_COUNT);  // Bounds check for below.
        |             ^~~~~~~~
  /home/heiher/git/dotnet/runtime/src/coreclr/src/vm/interpreter.cpp:3540:9: note: here
   3540 |         default:
        |         ^~~~~~~

@jkotas @am11 Request for review please.

[ghost]

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[am11]

LGTM. Tested your changes with clang, no issues.

[jkotas]

Thanks!