Revert "[libc][math] Implement issignaling macro." (#109992)

Reverts #109615

Author: lntue

libc/include/llvm-libc-macros/math-function-macros.h

@@ -20,9 +20,5 @@
   __builtin_fpclassify(FP_NAN, FP_INFINITE, FP_NORMAL, FP_SUBNORMAL, FP_ZERO, x)
 #define isnormal(x) __builtin_isnormal(x)
 #define issubnormal(x) (fpclassify(x) == FP_SUBNORMAL)
-#if (defined(__clang__) && __clang_major__ >= 18) ||                           \
-    (defined(__GNUC__) && __GNUC__ >= 13)
-#define issignaling(x) __builtin_issignaling(x)
-#endif
 
 #endif // LLVM_LIBC_MACROS_MATH_FUNCTION_MACROS_H

libc/test/include/CMakeLists.txt

@@ -81,36 +81,6 @@ add_libc_test(
     libc.include.llvm-libc-macros.stdckdint_macros
 )
 
-add_libc_test(
-  issignaling_test
-  SUITE
-    libc_include_tests
-  SRCS
-    issignaling_test.cpp
-  DEPENDS
-    libc.include.llvm-libc-macros.math_function_macros
-)
-
-add_libc_test(
-  issignalingf_test
-  SUITE
-    libc_include_tests
-  SRCS
-    issignalingf_test.cpp
-  DEPENDS
-    libc.include.llvm-libc-macros.math_function_macros
-)
-
-add_libc_test(
-  issignalingl_test
-  SUITE
-    libc_include_tests
-  SRCS
-    issignalingl_test.cpp
-  DEPENDS
-    libc.include.llvm-libc-macros.math_function_macros
-)
-
 add_libc_test(
   issubnormal_test
   SUITE
@@ -396,21 +366,6 @@ add_libc_test(
     libc.include.llvm-libc-macros.math_function_macros
 )
 
-add_libc_test(
-  issignaling_c_test
-  C_TEST
-  UNIT_TEST_ONLY
-  SUITE
-    libc_include_tests
-  SRCS
-    issignaling_test.c
-  COMPILE_OPTIONS
-    -Wall
-    -Werror
-  DEPENDS
-    libc.include.llvm-libc-macros.math_function_macros
-)
-
 add_libc_test(
   isinf_c_test
   C_TEST