Revert "[clang] Support fixed point types in C++ (#67750)" (#69963)

This reverts commit a3a7d631.

When compiling with MSVC2022 in  C++32 mode this is giving an error.
Compiling this simple test case:
t1.cpp:
with -std=c++23 will give the following error:

In file included from C:\Users\zahiraam\t1.cpp:1:
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3329:16:
error:
      compile with '-ffixed-point' to enable fixed point types
 3329 |         _Vbase _Accum = 0;
      |                ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3329:23:
error:
      expected unqualified-id
 3329 |         _Vbase _Accum = 0;
      |                       ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3334:13:
error:
      compile with '-ffixed-point' to enable fixed point types
 3334 |             _Accum |= _Tmp ? _Mask : _Vbase{0};
      |             ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3334:20:
error:
      expected unqualified-id
 3334 |             _Accum |= _Tmp ? _Mask : _Vbase{0};
      |                    ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3336:53:
error:
      expected '(' for function-style cast or type construction
 3336 |                 this->_Emplace_back_unchecked(_Accum);
      |                                               ~~~~~~^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3337:17:
error:
      compile with '-ffixed-point' to enable fixed point types
 3337 |                 _Accum = 0;
      |                 ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3337:24:
error:
      expected unqualified-id
 3337 |                 _Accum = 0;
      |                        ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3343:49:
error:
      expected '(' for function-style cast or type construction
 3343 |             this->_Emplace_back_unchecked(_Accum);
      |                                           ~~~~~~^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3352:16:
error:
      compile with '-ffixed-point' to enable fixed point types
 3352 |         _Vbase _Accum    = 0;
      |                ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3352:26:
error:
      expected unqualified-id
 3352 |         _Vbase _Accum    = 0;
      |                          ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3357:13:
error:
      compile with '-ffixed-point' to enable fixed point types
 3357 |             _Accum |= _Tmp ? _Mask : _Vbase{0};
      |             ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3357:20:
error:
      expected unqualified-id
 3357 |             _Accum |= _Tmp ? _Mask : _Vbase{0};
      |                    ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3359:46:
error:
      expected '(' for function-style cast or type construction
 3359 |                 this->_Myvec.push_back(_Accum);
      |                                        ~~~~~~^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3360:17:
error:
      compile with '-ffixed-point' to enable fixed point types
 3360 |                 _Accum = 0;
      |                 ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3360:24:
error:
      expected unqualified-id
 3360 |                 _Accum = 0;
      |                        ^
c:\Program files\Microsoft Visual
Studio\2022\Professional\VC\Tools\MSVC\14.35.32215\include\vector:3366:42:
error:
      expected '(' for function-style cast or type construction
 3366 |             this->_Myvec.push_back(_Accum);
      |                                    ~~~~~~^
16 errors generated.

See also comment here:
https://github.com/llvm/llvm-project/pull/67750#issuecomment-1775264907