Revert "[libc] wchar string conversion functions mb to wc" (#150549)

Reverts llvm/llvm-project#149423

Failing nullptr crash when using sanitizer

Author: sribee8

libc/config/linux/x86_64/entrypoints.txt

@@ -1266,9 +1266,6 @@ if(LLVM_LIBC_FULL_BUILD)
     libc.src.wchar.mbrlen
     libc.src.wchar.mbrtowc
     libc.src.wchar.mbtowc
-    libc.src.wchar.mbstowcs
-    libc.src.wchar.mbsrtowcs
-    libc.src.wchar.mbsnrtowcs
     libc.src.wchar.wcrtomb
     libc.src.wchar.wctomb
     libc.src.wchar.wcstombs

libc/include/wchar.yaml

@@ -53,33 +53,6 @@ functions:
       - type: wchar_t *__restrict
       - type: const char *__restrict
       - type: size_t
-  - name: mbsnrtowcs
-    standards:
-      - stdc
-    return_type: size_t
-    arguments:
-      - type: wchar_t *__restrict
-      - type: const char **__restrict
-      - type: size_t
-      - type: size_t
-      - type: mbstate_t *__restrict
-  - name: mbsrtowcs
-    standards:
-      - stdc
-    return_type: size_t
-    arguments:
-      - type: wchar_t *__restrict
-      - type: const char **__restrict
-      - type: size_t
-      - type: mbstate_t *__restrict
-  - name: mbstowcs
-    standards:
-      - stdc
-    return_type: size_t
-    arguments:
-      - type: wchar_t *__restrict
-      - type: const char *__restrict
-      - type: size_t
   - name: mblen
     standards:
       - stdc

libc/src/__support/wchar/CMakeLists.txt

@@ -60,31 +60,14 @@ add_object_library(
   SRCS
     mbrtowc.cpp
   DEPENDS
-    libc.hdr.errno_macros
-    libc.hdr.types.wchar_t
-    libc.hdr.types.size_t
-    libc.src.__support.common
-    libc.src.__support.error_or
-    libc.src.__support.macros.config
-    .character_converter
-    .mbstate
-)
-
-add_header_library(
-  mbsnrtowcs
-  HDRS
-    mbsnrtowcs.h
-  DEPENDS
-    libc.hdr.errno_macros
-    libc.hdr.types.wchar_t
-    libc.hdr.types.size_t
-    libc.src.__support.common
-    libc.src.__support.error_or
-    libc.src.__support.macros.config
-    libc.src.__support.macros.null_check
-    .character_converter
-    .mbstate
-    .string_converter
+  libc.hdr.errno_macros
+  libc.hdr.types.wchar_t
+  libc.hdr.types.size_t
+  libc.src.__support.common
+  libc.src.__support.error_or
+  libc.src.__support.macros.config
+  .character_converter
+  .mbstate
 )
 
 add_header_library(

libc/src/__support/wchar/mbsnrtowcs.h

@@ -169,54 +169,6 @@ add_entrypoint_object(
     libc.src.__support.wchar.mbstate
 )
 
-add_entrypoint_object(
-  mbstowcs
-  SRCS
-    mbstowcs.cpp
-  HDRS
-    mbstowcs.h
-  DEPENDS
-    libc.hdr.types.size_t
-    libc.hdr.types.wchar_t
-    libc.src.__support.common
-    libc.src.__support.macros.config
-    libc.src.__support.libc_errno
-    libc.src.__support.wchar.mbstate
-    libc.src.__support.wchar.mbsnrtowcs
-)
-
-add_entrypoint_object(
-  mbsrtowcs
-  SRCS
-    mbsrtowcs.cpp
-  HDRS
-    mbsrtowcs.h
-  DEPENDS
-    libc.hdr.types.size_t
-    libc.hdr.types.wchar_t
-    libc.src.__support.common
-    libc.src.__support.macros.config
-    libc.src.__support.libc_errno
-    libc.src.__support.wchar.mbstate
-    libc.src.__support.wchar.mbsnrtowcs
-)
-
-add_entrypoint_object(
-  mbsnrtowcs
-  SRCS
-    mbsnrtowcs.cpp
-  HDRS
-    mbsnrtowcs.h
-  DEPENDS
-    libc.hdr.types.size_t
-    libc.hdr.types.wchar_t
-    libc.src.__support.common
-    libc.src.__support.macros.config
-    libc.src.__support.libc_errno
-    libc.src.__support.wchar.mbstate
-    libc.src.__support.wchar.mbsnrtowcs
-)
-
 add_entrypoint_object(
   wcstombs
   SRCS